refactor(layout): consolidate backend codebase into backend/ package and clean root directory

- Moved cmd/, core/, plugins/, pkg/, downstream/, and main.go into backend/ directory
- Batch updated all Go source files to import github.com/Rain-kl/Wavelet/backend/...
- Updated Makefile, scripts/swagger.sh, architecture guards, and platform skills
- Passed all quality gates (100% tests, 0 lint issues, clean build)

backend/core/app.go

@@ -0,0 +1,492 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"os/signal"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+)
+
+const (
+	defaultShutdownTimeout = 10 * time.Second
+)
+
+// AppOption configures an App instance during construction.
+type AppOption func(*App)
+
+// WithContext sets a custom root Context for the App.
+func WithContext(ctx *Context) AppOption {
+	return func(a *App) {
+		if ctx != nil {
+			a.ctx = ctx
+		}
+	}
+}
+
+// WithProfile sets the runtime profile for the App.
+func WithProfile(profile Profile) AppOption {
+	return func(a *App) {
+		a.profile = normalizeProfile(profile)
+	}
+}
+
+// WithPlugins registers initial plugins for the App.
+func WithPlugins(plugins ...Plugin) AppOption {
+	return func(a *App) {
+		a.Use(plugins...)
+	}
+}
+
+// WithMigrationEngine sets the database migration engine for the App.
+func WithMigrationEngine(engine MigrationEngine) AppOption {
+	return func(a *App) {
+		a.migrationEngine = engine
+	}
+}
+
+// WithMigrationRunner sets the migration runner function for the App.
+func WithMigrationRunner(runner MigrationRunner) AppOption {
+	return func(a *App) {
+		a.migrationEngine = runner
+	}
+}
+
+// WithShutdownTimeout sets the fallback timeout for graceful application shutdown.
+func WithShutdownTimeout(timeout time.Duration) AppOption {
+	return func(a *App) {
+		if timeout > 0 {
+			a.shutdownTimeout = timeout
+		}
+	}
+}
+
+// App is the unified assembly entrypoint and runtime aspect dispatcher of the Cordis micro-kernel.
+// It manages plugin collection, dependency mounting, migration execution, profile-based driver startup,
+// and graceful signal-driven LIFO shutdown.
+type App struct {
+	mu              sync.RWMutex
+	ctx             *Context
+	profile         Profile
+	plugins         []Plugin
+	pluginMap       map[string]Plugin
+	applied         bool
+	running         bool
+	startedDrivers  []Driver
+	migrationEngine MigrationEngine
+	shutdownTimeout time.Duration
+}
+
+// NewApp creates a new Cordis application instance with default options.
+func NewApp(opts ...AppOption) *App {
+	app := &App{
+		ctx:             NewContext(context.Background()),
+		profile:         ProfileAll,
+		pluginMap:       make(map[string]Plugin),
+		shutdownTimeout: defaultShutdownTimeout,
+	}
+
+	for _, opt := range opts {
+		if opt != nil {
+			opt(app)
+		}
+	}
+
+	return app
+}
+
+// Context returns the root micro-kernel Context of the application.
+func (a *App) Context() *Context {
+	return a.ctx
+}
+
+// Profile returns the current runtime profile of the application.
+func (a *App) Profile() Profile {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+	return a.profile
+}
+
+// WithProfile sets the application runtime profile and returns the App for fluent chaining.
+func (a *App) WithProfile(profile Profile) *App {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	a.profile = normalizeProfile(profile)
+	return a
+}
+
+// SetProfile sets the application runtime profile.
+func (a *App) SetProfile(profile Profile) *App {
+	return a.WithProfile(profile)
+}
+
+// Use registers one or more plugins into the application in registration order.
+// Duplicate plugins (by Name) update existing registrations in-place to preserve order.
+func (a *App) Use(plugins ...Plugin) *App {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+
+	for _, p := range plugins {
+		if p == nil {
+			continue
+		}
+		name := p.Name()
+		if name == "" {
+			continue
+		}
+
+		if _, exists := a.pluginMap[name]; exists {
+			for i, existing := range a.plugins {
+				if existing.Name() == name {
+					a.plugins[i] = p
+					break
+				}
+			}
+		} else {
+			a.plugins = append(a.plugins, p)
+		}
+		a.pluginMap[name] = p
+	}
+
+	return a
+}
+
+// Plugins returns a copy of all registered plugins in registration order.
+func (a *App) Plugins() []Plugin {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+
+	res := make([]Plugin, len(a.plugins))
+	copy(res, a.plugins)
+	return res
+}
+
+// Plugin retrieves a registered plugin by its unique name.
+func (a *App) Plugin(name string) (Plugin, bool) {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+
+	p, ok := a.pluginMap[name]
+	return p, ok
+}
+
+// SetMigrationEngine sets the migration engine for the application.
+func (a *App) SetMigrationEngine(engine MigrationEngine) *App {
+	a.mu.Lock()
+	defer a.mu.Unlock()
+	a.migrationEngine = engine
+	return a
+}
+
+// SetMigrationRunner sets the migration runner function for the application.
+func (a *App) SetMigrationRunner(runner MigrationRunner) *App {
+	return a.SetMigrationEngine(runner)
+}
+
+// ApplyPlugins applies all registered plugins on the application Context.
+// It is idempotent and only applies plugins once per App instance.
+func (a *App) ApplyPlugins() error {
+	a.mu.Lock()
+	if a.applied {
+		a.mu.Unlock()
+		return nil
+	}
+	a.applied = true
+	plugins := make([]Plugin, len(a.plugins))
+	copy(plugins, a.plugins)
+	a.mu.Unlock()
+
+	for _, p := range plugins {
+		if err := p.Apply(a.ctx); err != nil {
+			return fmt.Errorf("core: apply plugin %q failed: %w", p.Name(), err)
+		}
+	}
+	return nil
+}
+
+// RunMigrations dispatches migration execution across all registered plugin migration entries.
+func (a *App) RunMigrations() error {
+	entries := a.ctx.Migrations().Entries()
+	if len(entries) == 0 {
+		return nil
+	}
+
+	a.mu.RLock()
+	engine := a.migrationEngine
+	a.mu.RUnlock()
+
+	if engine == nil {
+		// Attempt to resolve from IoC container
+		if resolved, err := Inject[MigrationEngine](a.ctx); err == nil && resolved != nil {
+			engine = resolved
+		}
+	}
+
+	if engine == nil {
+		return nil
+	}
+
+	if err := engine.Migrate(a.ctx, entries); err != nil {
+		return fmt.Errorf("core: migration failed: %w", err)
+	}
+
+	return nil
+}
+
+// Start executes the application boot pipeline:
+// 1. Applies all registered plugins to populate services, routes, tasks, and drivers.
+// 2. Dispatches database migrations via MigrationEngine.
+// 3. Filters and starts drivers matching the active Profile.
+// 4. Emits "app:ready" on the EventBus.
+//
+//nolint:contextcheck
+func (a *App) Start(ctx ...context.Context) error {
+	a.mu.Lock()
+	if a.running {
+		a.mu.Unlock()
+		return ErrAppRunning
+	}
+	a.running = true
+	a.mu.Unlock()
+
+	var baseCtx context.Context
+	switch {
+	case len(ctx) > 0 && ctx[0] != nil:
+		baseCtx = ctx[0]
+	case a.ctx != nil:
+		baseCtx = a.ctx.GoContext()
+	default:
+		baseCtx = context.Background()
+	}
+
+	// 1. Apply plugins
+	if err := a.ApplyPlugins(); err != nil {
+		a.mu.Lock()
+		a.running = false
+		a.mu.Unlock()
+		return err
+	}
+
+	// 2. Run migrations
+	if err := a.RunMigrations(); err != nil {
+		a.mu.Lock()
+		a.running = false
+		a.mu.Unlock()
+		return err
+	}
+
+	// 3. Filter drivers matching active profile
+	a.mu.RLock()
+	prof := a.profile
+	a.mu.RUnlock()
+
+	allDrivers := a.ctx.Drivers()
+	var driversToStart []Driver
+	for _, d := range allDrivers {
+		if matchesProfile(prof, d.Type()) {
+			driversToStart = append(driversToStart, d)
+		}
+	}
+
+	// 4. Start matching drivers
+	for _, d := range driversToStart {
+		if err := d.Start(baseCtx); err != nil {
+			// Rollback already started drivers in reverse order
+			a.mu.Lock()
+			started := a.startedDrivers
+			a.startedDrivers = nil
+			a.running = false
+			a.mu.Unlock()
+
+			for i := len(started) - 1; i >= 0; i-- {
+				_ = started[i].Stop(context.Background())
+			}
+
+			return fmt.Errorf("core: start driver %s failed: %w", d.Type(), err)
+		}
+
+		a.mu.Lock()
+		a.startedDrivers = append(a.startedDrivers, d)
+		a.mu.Unlock()
+	}
+
+	// 5. Emit app:ready event
+	_ = a.ctx.Events().Emit(baseCtx, "app:ready", a)
+
+	return nil
+}
+
+// Stop gracefully shuts down the application:
+// 1. Emits "app:stopping" on the EventBus.
+// 2. Stops all started drivers in LIFO (reverse) order.
+// 3. Disposes the Context (running registered OnDispose callbacks in LIFO order).
+// 4. Emits "app:stopped" on the EventBus.
+//
+//nolint:contextcheck
+func (a *App) Stop(ctx ...context.Context) error {
+	a.mu.Lock()
+	if !a.running {
+		a.mu.Unlock()
+		return nil
+	}
+	a.running = false
+	started := a.startedDrivers
+	a.startedDrivers = nil
+	timeout := a.shutdownTimeout
+	a.mu.Unlock()
+
+	var shutdownCtx context.Context
+	if len(ctx) > 0 && ctx[0] != nil {
+		shutdownCtx = ctx[0]
+	} else {
+		var cancel context.CancelFunc
+		shutdownCtx, cancel = context.WithTimeout(context.Background(), timeout)
+		defer cancel()
+	}
+
+	_ = a.ctx.Events().Emit(shutdownCtx, "app:stopping", a)
+
+	var errs []error
+
+	// 1. Stop drivers in reverse order
+	for i := len(started) - 1; i >= 0; i-- {
+		d := started[i]
+		if err := d.Stop(shutdownCtx); err != nil {
+			errs = append(errs, fmt.Errorf("core: stop driver %s failed: %w", d.Type(), err))
+		}
+	}
+
+	// 2. Dispose context
+	if a.ctx != nil && !a.ctx.IsDisposed() {
+		if err := a.ctx.Dispose(); err != nil {
+			errs = append(errs, fmt.Errorf("core: dispose context failed: %w", err))
+		}
+	}
+
+	_ = a.ctx.Events().Emit(shutdownCtx, "app:stopped", a)
+
+	return errors.Join(errs...)
+}
+
+// Run starts the application and blocks until an OS signal (SIGINT, SIGTERM) or context cancellation is received,
+// then executes graceful shutdown.
+//
+//nolint:contextcheck
+func (a *App) Run(ctx ...context.Context) error {
+	var parent context.Context
+	switch {
+	case len(ctx) > 0 && ctx[0] != nil:
+		parent = ctx[0]
+	case a.ctx != nil:
+		parent = a.ctx.GoContext()
+	default:
+		parent = context.Background()
+	}
+
+	sigCtx, stopSignals := signal.NotifyContext(parent, syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
+	defer stopSignals()
+
+	if err := a.Start(sigCtx); err != nil {
+		return err
+	}
+
+	// Wait for OS signal or context cancellation
+	<-sigCtx.Done()
+
+	shutdownCtx, cancel := context.WithTimeout(context.Background(), a.shutdownTimeout)
+	defer cancel()
+
+	return a.Stop(shutdownCtx)
+}
+
+// IsRunning returns whether the application is currently running.
+func (a *App) IsRunning() bool {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+	return a.running
+}
+
+// StartedDrivers returns a copy of currently running drivers.
+func (a *App) StartedDrivers() []Driver {
+	a.mu.RLock()
+	defer a.mu.RUnlock()
+
+	res := make([]Driver, len(a.startedDrivers))
+	copy(res, a.startedDrivers)
+	return res
+}
+
+// ExecuteCLI parses CLI arguments to configure the profile and runs the application.
+func (a *App) ExecuteCLI(args ...string) error {
+	var ctx context.Context
+	if a.ctx != nil {
+		ctx = a.ctx.GoContext()
+	} else {
+		ctx = context.Background()
+	}
+	return a.ExecuteCLIWithContext(ctx, args...)
+}
+
+// ExecuteCLIWithContext parses CLI arguments, configures the profile, and runs the application with the given context.
+//
+//nolint:contextcheck
+func (a *App) ExecuteCLIWithContext(ctx context.Context, args ...string) error {
+	cliArgs := args
+	if len(cliArgs) == 0 {
+		cliArgs = os.Args[1:]
+	}
+
+	profile := ProfileAll
+	if len(cliArgs) > 0 {
+		first := strings.TrimSpace(cliArgs[0])
+		switch {
+		case strings.HasPrefix(first, "--profile="):
+			profile = Profile(strings.TrimPrefix(first, "--profile="))
+		case strings.HasPrefix(first, "-p="):
+			profile = Profile(strings.TrimPrefix(first, "-p="))
+		case !strings.HasPrefix(first, "-"):
+			profile = Profile(first)
+		}
+	}
+
+	a.WithProfile(profile)
+	return a.Run(ctx)
+}
+
+func matchesProfile(profile Profile, dt DriverType) bool {
+	norm := normalizeProfile(profile)
+	switch norm {
+	case ProfileAll, "":
+		return true
+	case ProfileAPI:
+		return dt == DriverTypeHTTP
+	case ProfileWorker:
+		return dt == DriverTypeWorker
+	case ProfileSchedule:
+		return dt == DriverTypeScheduler
+	default:
+		return string(norm) == string(dt)
+	}
+}
+
+func normalizeProfile(p Profile) Profile {
+	switch strings.ToLower(strings.TrimSpace(string(p))) {
+	case "api", "http":
+		return ProfileAPI
+	case "worker":
+		return ProfileWorker
+	case "schedule", "scheduler", "cron":
+		return ProfileSchedule
+	case "all", "fused", "full", "":
+		return ProfileAll
+	default:
+		return p
+	}
+}

backend/core/app_test.go

@@ -0,0 +1,507 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core_test
+
+import (
+	"context"
+	"errors"
+	"sync"
+	"testing"
+	"testing/fstest"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/Rain-kl/Wavelet/backend/core"
+	"github.com/Rain-kl/Wavelet/backend/core/extpoints"
+)
+
+// appMockDriver is a test driver tracking its start/stop lifecycle.
+type appMockDriver struct {
+	mu          sync.Mutex
+	driverType  core.DriverType
+	startCalled bool
+	stopCalled  bool
+	startErr    error
+	stopErr     error
+}
+
+func newAppMockDriver(dt core.DriverType) *appMockDriver {
+	return &appMockDriver{driverType: dt}
+}
+
+func (m *appMockDriver) Type() core.DriverType {
+	return m.driverType
+}
+
+func (m *appMockDriver) Start(_ context.Context) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.startErr != nil {
+		return m.startErr
+	}
+	m.startCalled = true
+	return nil
+}
+
+func (m *appMockDriver) Stop(_ context.Context) error {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	if m.stopErr != nil {
+		return m.stopErr
+	}
+	m.stopCalled = true
+	return nil
+}
+
+func (m *appMockDriver) isStarted() bool {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return m.startCalled
+}
+
+func (m *appMockDriver) isStopped() bool {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+	return m.stopCalled
+}
+
+// appMockPlugin is a test plugin.
+type appMockPlugin struct {
+	name    string
+	applyFn func(ctx *core.Context) error
+}
+
+func (p *appMockPlugin) Name() string {
+	return p.name
+}
+
+func (p *appMockPlugin) Apply(ctx *core.Context) error {
+	if p.applyFn != nil {
+		return p.applyFn(ctx)
+	}
+	return nil
+}
+
+func TestAppNewAndConfiguration(t *testing.T) {
+	customCtx := core.NewContext(context.Background())
+	p1 := &appMockPlugin{name: "plugin1"}
+	p2 := &appMockPlugin{name: "plugin2"}
+
+	app := core.NewApp(
+		core.WithContext(customCtx),
+		core.WithProfile(core.ProfileAPI),
+		core.WithPlugins(p1, p2),
+		core.WithShutdownTimeout(5*time.Second),
+	)
+
+	assert.Equal(t, customCtx, app.Context())
+	assert.Equal(t, core.ProfileAPI, app.Profile())
+	assert.Len(t, app.Plugins(), 2)
+
+	retrieved, ok := app.Plugin("plugin1")
+	assert.True(t, ok)
+	assert.Equal(t, p1, retrieved)
+
+	_, ok = app.Plugin("non_existent")
+	assert.False(t, ok)
+
+	// Update existing plugin in-place
+	p1Updated := &appMockPlugin{name: "plugin1"}
+	app.Use(p1Updated, nil)
+	assert.Len(t, app.Plugins(), 2)
+	retrieved, ok = app.Plugin("plugin1")
+	assert.True(t, ok)
+	assert.Equal(t, p1Updated, retrieved)
+
+	// Test SetProfile
+	app.SetProfile(core.ProfileWorker)
+	assert.Equal(t, core.ProfileWorker, app.Profile())
+}
+
+func TestAppProfileDispatch(t *testing.T) {
+	tests := []struct {
+		name           string
+		profile        core.Profile
+		expectedHTTP   bool
+		expectedWorker bool
+		expectedCron   bool
+		expectedCustom bool
+	}{
+		{
+			name:           "ProfileAPI only starts HTTP driver",
+			profile:        core.ProfileAPI,
+			expectedHTTP:   true,
+			expectedWorker: false,
+			expectedCron:   false,
+			expectedCustom: false,
+		},
+		{
+			name:           "ProfileWorker only starts Worker driver",
+			profile:        core.ProfileWorker,
+			expectedHTTP:   false,
+			expectedWorker: true,
+			expectedCron:   false,
+			expectedCustom: false,
+		},
+		{
+			name:           "ProfileSchedule only starts Schedule driver",
+			profile:        core.ProfileSchedule,
+			expectedHTTP:   false,
+			expectedWorker: false,
+			expectedCron:   true,
+			expectedCustom: false,
+		},
+		{
+			name:           "Profile 'scheduler' alias starts Schedule driver",
+			profile:        core.Profile("scheduler"),
+			expectedHTTP:   false,
+			expectedWorker: false,
+			expectedCron:   true,
+			expectedCustom: false,
+		},
+		{
+			name:           "ProfileAll starts all drivers",
+			profile:        core.ProfileAll,
+			expectedHTTP:   true,
+			expectedWorker: true,
+			expectedCron:   true,
+			expectedCustom: true,
+		},
+		{
+			name:           "Custom profile starts custom driver",
+			profile:        core.Profile("custom_rpc"),
+			expectedHTTP:   false,
+			expectedWorker: false,
+			expectedCron:   false,
+			expectedCustom: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			httpD := newAppMockDriver(core.DriverTypeHTTP)
+			workerD := newAppMockDriver(core.DriverTypeWorker)
+			cronD := newAppMockDriver(core.DriverTypeScheduler)
+			customD := newAppMockDriver(core.DriverType("custom_rpc"))
+
+			p := &appMockPlugin{
+				name: "drivers_plugin",
+				applyFn: func(ctx *core.Context) error {
+					_ = ctx.RegisterDriver(httpD)
+					_ = ctx.RegisterDriver(workerD)
+					_ = ctx.RegisterDriver(cronD)
+					_ = ctx.RegisterDriver(customD)
+					return nil
+				},
+			}
+
+			app := core.NewApp(
+				core.WithProfile(tt.profile),
+				core.WithPlugins(p),
+			)
+
+			err := app.Start(context.Background())
+			require.NoError(t, err)
+
+			assert.Equal(t, tt.expectedHTTP, httpD.isStarted(), "HTTP driver start mismatch")
+			assert.Equal(t, tt.expectedWorker, workerD.isStarted(), "Worker driver start mismatch")
+			assert.Equal(t, tt.expectedCron, cronD.isStarted(), "Cron driver start mismatch")
+			assert.Equal(t, tt.expectedCustom, customD.isStarted(), "Custom driver start mismatch")
+
+			err = app.Stop(context.Background())
+			require.NoError(t, err)
+		})
+	}
+}
+
+func TestAppLifecycleStartStop(t *testing.T) {
+	var stopOrder []string
+	var stopOrderMu sync.Mutex
+
+	httpD := newAppMockDriver(core.DriverTypeHTTP)
+	workerD := newAppMockDriver(core.DriverTypeWorker)
+
+	httpD.stopErr = nil
+	workerD.stopErr = nil
+
+	// Wrap stop to record order
+	origHttpStop := httpD.Stop
+	_ = origHttpStop
+
+	p := &appMockPlugin{
+		name: "test_plugin",
+		applyFn: func(ctx *core.Context) error {
+			_ = ctx.RegisterDriver(httpD)
+			_ = ctx.RegisterDriver(workerD)
+
+			ctx.OnDispose(func() error {
+				stopOrderMu.Lock()
+				stopOrder = append(stopOrder, "ctx_disposer")
+				stopOrderMu.Unlock()
+				return nil
+			})
+			return nil
+		},
+	}
+
+	app := core.NewApp(
+		core.WithProfile(core.ProfileAll),
+		core.WithPlugins(p),
+	)
+
+	var readyReceived, stoppingReceived, stoppedReceived bool
+	app.Context().Events().On("app:ready", func() {
+		readyReceived = true
+	})
+	app.Context().Events().On("app:stopping", func() {
+		stoppingReceived = true
+	})
+	app.Context().Events().On("app:stopped", func() {
+		stoppedReceived = true
+	})
+
+	err := app.Start(context.Background())
+	require.NoError(t, err)
+	assert.True(t, app.IsRunning())
+	assert.Len(t, app.StartedDrivers(), 2)
+	assert.True(t, readyReceived)
+
+	err = app.Stop(context.Background())
+	require.NoError(t, err)
+	assert.False(t, app.IsRunning())
+	assert.Empty(t, app.StartedDrivers())
+	assert.True(t, stoppingReceived)
+	assert.True(t, stoppedReceived)
+
+	assert.True(t, httpD.isStopped())
+	assert.True(t, workerD.isStopped())
+	assert.True(t, app.Context().IsDisposed())
+
+	stopOrderMu.Lock()
+	assert.Contains(t, stopOrder, "ctx_disposer")
+	stopOrderMu.Unlock()
+}
+
+func TestAppStartDriverFailureRollback(t *testing.T) {
+	driver1 := newAppMockDriver(core.DriverTypeHTTP)
+	driver2 := newAppMockDriver(core.DriverTypeWorker)
+	driver2.startErr = errors.New("worker listen port conflict")
+	driver3 := newAppMockDriver(core.DriverTypeScheduler)
+
+	p := &appMockPlugin{
+		name: "fail_driver_plugin",
+		applyFn: func(ctx *core.Context) error {
+			_ = ctx.RegisterDriver(driver1)
+			_ = ctx.RegisterDriver(driver2)
+			_ = ctx.RegisterDriver(driver3)
+			return nil
+		},
+	}
+
+	app := core.NewApp(
+		core.WithProfile(core.ProfileAll),
+		core.WithPlugins(p),
+	)
+
+	err := app.Start(context.Background())
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "worker listen port conflict")
+	assert.False(t, app.IsRunning())
+
+	// Driver 1 was started then rolled back (stopped)
+	assert.True(t, driver1.isStarted())
+	assert.True(t, driver1.isStopped())
+
+	// Driver 3 was never started
+	assert.False(t, driver3.isStarted())
+}
+
+func TestAppMigrationEngineExecution(t *testing.T) {
+	var migratedEntries []extpoints.MigrationEntry
+	runner := core.MigrationRunner(func(ctx *core.Context, entries []extpoints.MigrationEntry) error {
+		migratedEntries = entries
+		return nil
+	})
+
+	sqlFS := fstest.MapFS{
+		"migrations/001_init.sql": &fstest.MapFile{Data: []byte("CREATE TABLE users(id int);")},
+	}
+
+	p := &appMockPlugin{
+		name: "auth",
+		applyFn: func(ctx *core.Context) error {
+			ctx.Migrations().Register("auth", sqlFS)
+			return nil
+		},
+	}
+
+	app := core.NewApp(
+		core.WithProfile(core.ProfileAll),
+		core.WithPlugins(p),
+		core.WithMigrationRunner(runner),
+	)
+
+	err := app.Start(context.Background())
+	require.NoError(t, err)
+	defer func() { _ = app.Stop(context.Background()) }()
+
+	require.Len(t, migratedEntries, 1)
+	assert.Equal(t, "auth", migratedEntries[0].PluginID)
+}
+
+func TestAppMigrationEngineFromIoCContainer(t *testing.T) {
+	var executed bool
+	runner := core.MigrationRunner(func(ctx *core.Context, entries []extpoints.MigrationEntry) error {
+		executed = true
+		return nil
+	})
+
+	sqlFS := fstest.MapFS{
+		"migrations/001_init.sql": &fstest.MapFile{Data: []byte("CREATE TABLE logs(id int);")},
+	}
+
+	p := &appMockPlugin{
+		name: "logstore",
+		applyFn: func(ctx *core.Context) error {
+			ctx.Migrations().Register("logstore", sqlFS)
+			core.Provide[core.MigrationEngine](ctx, runner)
+			return nil
+		},
+	}
+
+	app := core.NewApp(
+		core.WithProfile(core.ProfileAll),
+		core.WithPlugins(p),
+	)
+
+	err := app.Start(context.Background())
+	require.NoError(t, err)
+	defer func() { _ = app.Stop(context.Background()) }()
+
+	assert.True(t, executed)
+}
+
+func TestAppRunContextCancellation(t *testing.T) {
+	d := newAppMockDriver(core.DriverTypeHTTP)
+	p := &appMockPlugin{
+		name: "http_plugin",
+		applyFn: func(ctx *core.Context) error {
+			return ctx.RegisterDriver(d)
+		},
+	}
+
+	app := core.NewApp(
+		core.WithProfile(core.ProfileAPI),
+		core.WithPlugins(p),
+		core.WithShutdownTimeout(1*time.Second),
+	)
+
+	ctx, cancel := context.WithCancel(context.Background())
+
+	errCh := make(chan error, 1)
+	go func() {
+		errCh <- app.Run(ctx)
+	}()
+
+	// Wait briefly then cancel
+	time.Sleep(50 * time.Millisecond)
+	assert.True(t, app.IsRunning())
+	assert.True(t, d.isStarted())
+
+	cancel()
+
+	select {
+	case err := <-errCh:
+		assert.NoError(t, err)
+		assert.False(t, app.IsRunning())
+		assert.True(t, d.isStopped())
+	case <-time.After(3 * time.Second):
+		t.Fatal("app.Run did not terminate upon context cancellation")
+	}
+}
+
+func TestAppExecuteCLI(t *testing.T) {
+	// Test CLI argument parsing logic
+	tests := []struct {
+		args            []string
+		expectedProfile core.Profile
+	}{
+		{args: []string{"api"}, expectedProfile: core.ProfileAPI},
+		{args: []string{"worker"}, expectedProfile: core.ProfileWorker},
+		{args: []string{"scheduler"}, expectedProfile: core.ProfileSchedule},
+		{args: []string{"schedule"}, expectedProfile: core.ProfileSchedule},
+		{args: []string{"all"}, expectedProfile: core.ProfileAll},
+		{args: []string{"--profile=worker"}, expectedProfile: core.ProfileWorker},
+		{args: []string{"-p=api"}, expectedProfile: core.ProfileAPI},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.args[0], func(t *testing.T) {
+			ctx, cancel := context.WithCancel(context.Background())
+			cancel() // cancel immediately
+
+			// Use custom root context to control cancellation
+			customApp := core.NewApp(core.WithContext(core.NewContext(ctx)))
+			_ = customApp.ExecuteCLI(tt.args...)
+			assert.Equal(t, tt.expectedProfile, customApp.Profile())
+		})
+	}
+}
+
+func TestAppIdempotencyAndErrorStates(t *testing.T) {
+	app := core.NewApp()
+
+	// Double start returns error
+	err := app.Start(context.Background())
+	require.NoError(t, err)
+
+	err = app.Start(context.Background())
+	assert.ErrorIs(t, err, core.ErrAppRunning)
+
+	// Stop clears running state
+	err = app.Stop(context.Background())
+	require.NoError(t, err)
+
+	// Double stop succeeds
+	err = app.Stop(context.Background())
+	require.NoError(t, err)
+
+	// Plugin apply failure
+	failPlugin := &appMockPlugin{
+		name: "failing_plugin",
+		applyFn: func(ctx *core.Context) error {
+			return errors.New("plugin init boom")
+		},
+	}
+	app2 := core.NewApp(core.WithPlugins(failPlugin))
+	err = app2.Start(context.Background())
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "plugin init boom")
+	assert.False(t, app2.IsRunning())
+
+	// Migration failure
+	migFailRunner := core.MigrationRunner(func(ctx *core.Context, entries []extpoints.MigrationEntry) error {
+		return errors.New("sql migrate error")
+	})
+	sqlFS := fstest.MapFS{
+		"migrations/001.sql": &fstest.MapFile{Data: []byte("...")},
+	}
+	migPlugin := &appMockPlugin{
+		name: "db_plugin",
+		applyFn: func(ctx *core.Context) error {
+			ctx.Migrations().Register("db_plugin", sqlFS)
+			return nil
+		},
+	}
+	app3 := core.NewApp(
+		core.WithPlugins(migPlugin),
+		core.WithMigrationRunner(migFailRunner),
+	)
+	err = app3.Start(context.Background())
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "sql migrate error")
+	assert.False(t, app3.IsRunning())
+}

backend/core/container.go

@@ -0,0 +1,193 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package core provides the micro-kernel service bus, generic IoC container, and runtime extensions.
+package core
+
+import (
+	"fmt"
+	"reflect"
+	"sync"
+)
+
+// Container manages service registration and resolution using Go reflection and generics.
+type Container struct {
+	mu        sync.RWMutex
+	parent    *Container
+	services  map[reflect.Type]any
+	listeners map[reflect.Type][]func(any)
+}
+
+// NewContainer creates a new IoC container instance with an optional parent container.
+func NewContainer(parent *Container) *Container {
+	return &Container{
+		parent:    parent,
+		services:  make(map[reflect.Type]any),
+		listeners: make(map[reflect.Type][]func(any)),
+	}
+}
+
+func isNil(i any) bool {
+	if i == nil {
+		return true
+	}
+	v := reflect.ValueOf(i)
+	switch v.Kind() {
+	case reflect.Chan, reflect.Func, reflect.Map, reflect.Pointer, reflect.UnsafePointer, reflect.Interface, reflect.Slice:
+		return v.IsNil()
+	default:
+		return false
+	}
+}
+
+// Provide registers a typed service implementation into the Context's IoC container.
+func Provide[T any](ctx *Context, service T) {
+	if ctx == nil {
+		panic("core: nil context provided to Provide")
+	}
+	if isNil(service) {
+		panic("core: cannot provide nil service")
+	}
+
+	targetType := reflect.TypeFor[T]()
+	ctx.Container().provide(targetType, service)
+}
+
+func (c *Container) provide(targetType reflect.Type, service any) {
+	c.mu.Lock()
+	c.services[targetType] = service
+
+	// Collect any matching listeners to invoke outside the lock
+	var callbacks []func(any)
+	svcType := reflect.TypeOf(service)
+	for lType, cbs := range c.listeners {
+		if lType == targetType || (lType.Kind() == reflect.Interface && svcType.Implements(lType)) {
+			callbacks = append(callbacks, cbs...)
+		}
+	}
+	c.mu.Unlock()
+
+	for _, cb := range callbacks {
+		cb(service)
+	}
+}
+
+// Inject resolves a registered service of type T from the Context.
+func Inject[T any](ctx *Context) (T, error) {
+	var zero T
+	if ctx == nil {
+		return zero, ErrNilContext
+	}
+
+	targetType := reflect.TypeFor[T]()
+	val, err := ctx.Container().resolve(targetType)
+	if err != nil {
+		return zero, err
+	}
+
+	typedVal, ok := val.(T)
+	if !ok {
+		return zero, fmt.Errorf("%w: cannot cast %T to %v", ErrServiceNotFound, val, targetType)
+	}
+	return typedVal, nil
+}
+
+func (c *Container) resolve(targetType reflect.Type) (any, error) {
+	c.mu.RLock()
+	// 1. Direct type match
+	if val, ok := c.services[targetType]; ok {
+		c.mu.RUnlock()
+		return val, nil
+	}
+
+	// 2. Interface assignment scan
+	if targetType.Kind() == reflect.Interface {
+		for _, val := range c.services {
+			if reflect.TypeOf(val).Implements(targetType) {
+				c.mu.RUnlock()
+				return val, nil
+			}
+		}
+	}
+	c.mu.RUnlock()
+
+	// 3. Fallback to parent container
+	if c.parent != nil {
+		return c.parent.resolve(targetType)
+	}
+
+	return nil, fmt.Errorf("%w: %v", ErrServiceNotFound, targetType)
+}
+
+// MustInject resolves a service of type T or panics if the service is not found.
+func MustInject[T any](ctx *Context) T {
+	s, err := Inject[T](ctx)
+	if err != nil {
+		panic(fmt.Sprintf("core: failed to inject service %v: %v", reflect.TypeFor[T](), err))
+	}
+	return s
+}
+
+// Has returns true if a service of type T is registered and resolvable in the Context.
+func Has[T any](ctx *Context) bool {
+	_, err := Inject[T](ctx)
+	return err == nil
+}
+
+// Using executes the given function synchronously if the required dependency is ready.
+func Using[T1 any](ctx *Context, fn func(s1 T1)) error {
+	s1, err := Inject[T1](ctx)
+	if err != nil {
+		return fmt.Errorf("%w: %w", ErrServiceNotReady, err)
+	}
+	fn(s1)
+	return nil
+}
+
+// Using2 executes the given function synchronously if both required dependencies are ready.
+func Using2[T1, T2 any](ctx *Context, fn func(s1 T1, s2 T2)) error {
+	s1, err1 := Inject[T1](ctx)
+	s2, err2 := Inject[T2](ctx)
+	if err1 != nil || err2 != nil {
+		return fmt.Errorf("%w: (dep1: %v, dep2: %v)", ErrServiceNotReady, err1, err2)
+	}
+	fn(s1, s2)
+	return nil
+}
+
+// Using3 executes the given function synchronously if all 3 required dependencies are ready.
+func Using3[T1, T2, T3 any](ctx *Context, fn func(s1 T1, s2 T2, s3 T3)) error {
+	s1, err1 := Inject[T1](ctx)
+	s2, err2 := Inject[T2](ctx)
+	s3, err3 := Inject[T3](ctx)
+	if err1 != nil || err2 != nil || err3 != nil {
+		return fmt.Errorf("%w: (dep1: %v, dep2: %v, dep3: %v)", ErrServiceNotReady, err1, err2, err3)
+	}
+	fn(s1, s2, s3)
+	return nil
+}
+
+// When registers a reactive hook that is called immediately if T is already provided,
+// or called as soon as T is provided in the future.
+func When[T any](ctx *Context, fn func(s T)) {
+	if ctx == nil {
+		panic("core: nil context provided to When")
+	}
+
+	targetType := reflect.TypeFor[T]()
+	c := ctx.Container()
+
+	// If already ready, execute immediately
+	if s, err := Inject[T](ctx); err == nil {
+		fn(s)
+	}
+
+	// Also register listener for future calls / updates
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.listeners[targetType] = append(c.listeners[targetType], func(val any) {
+		if typed, ok := val.(T); ok {
+			fn(typed)
+		}
+	})
+}

backend/core/context.go

@@ -0,0 +1,341 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/Rain-kl/Wavelet/backend/core/extpoints"
+)
+
+// Context is the central micro-kernel service bus and runtime lifecycle container.
+// It embeds Go standard context.Context compatibility, hierarchical scoping,
+// service resolution, and LIFO disposer teardown.
+type Context struct {
+	goCtx     context.Context
+	cancel    context.CancelFunc
+	parent    *Context
+	container *Container
+
+	events     *EventBus
+	router     extpoints.RouterExtension
+	migrations extpoints.MigrationExtension
+	tasks      extpoints.TaskExtension
+	schedules  extpoints.ScheduleExtension
+	settings   extpoints.SettingExtension
+
+	mu        sync.RWMutex
+	children  []*Context
+	disposers []Disposer
+	drivers   []Driver
+	values    map[any]any
+	disposed  bool
+}
+
+// NewContext creates a new root Context wrapping a standard Go context.
+// If base is nil, context.Background() is used by default.
+//
+//nolint:contextcheck
+func NewContext(base context.Context) *Context {
+	if base == nil {
+		base = context.Background()
+	}
+	ctx, cancel := context.WithCancel(base)
+
+	return &Context{
+		goCtx:      ctx,
+		cancel:     cancel,
+		container:  NewContainer(nil),
+		events:     NewEventBus(),
+		router:     extpoints.NewRouterRegistry(),
+		migrations: extpoints.NewMigrationRegistry(),
+		tasks:      extpoints.NewTaskRegistry(),
+		schedules:  extpoints.NewScheduleRegistry(),
+		settings:   extpoints.NewSettingRegistry(),
+		values:     make(map[any]any),
+	}
+}
+
+// Deadline returns the time when work done on behalf of this context should be canceled.
+func (c *Context) Deadline() (deadline time.Time, ok bool) {
+	return c.goCtx.Deadline()
+}
+
+// Done returns a channel that's closed when work done on behalf of this context should be canceled.
+func (c *Context) Done() <-chan struct{} {
+	return c.goCtx.Done()
+}
+
+// Err returns a non-nil error value after Done is closed.
+func (c *Context) Err() error {
+	return c.goCtx.Err()
+}
+
+// Value returns the value associated with key, searching the local values map,
+// the underlying Go context, and fallback parent Contexts.
+func (c *Context) Value(key any) any {
+	c.mu.RLock()
+	if v, ok := c.values[key]; ok {
+		c.mu.RUnlock()
+		return v
+	}
+	c.mu.RUnlock()
+
+	if v := c.goCtx.Value(key); v != nil {
+		return v
+	}
+
+	if c.parent != nil {
+		return c.parent.Value(key)
+	}
+
+	return nil
+}
+
+// GoContext returns the underlying standard Go context.Context.
+func (c *Context) GoContext() context.Context {
+	return c.goCtx
+}
+
+// Set stores an arbitrary key-value pair in this Context's local storage.
+func (c *Context) Set(key any, val any) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	if c.values == nil {
+		c.values = make(map[any]any)
+	}
+	c.values[key] = val
+}
+
+// Get retrieves a key-value pair from this Context's local storage.
+func (c *Context) Get(key any) (any, bool) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	if c.values == nil {
+		return nil, false
+	}
+	v, ok := c.values[key]
+	return v, ok
+}
+
+// Container returns the underlying IoC container for this Context.
+func (c *Context) Container() *Container {
+	return c.container
+}
+
+// Parent returns the parent Context, or nil if this is a root Context.
+func (c *Context) Parent() *Context {
+	return c.parent
+}
+
+// Fork creates a child Context with its own scoped IoC container and values,
+// linked to this Context for hierarchical fallback resolution and cascading teardown.
+func (c *Context) Fork() *Context {
+	return c.ForkWithContext(c.goCtx)
+}
+
+// ForkWithContext creates a child Context using a specific standard Go context.
+//
+//nolint:contextcheck
+func (c *Context) ForkWithContext(base context.Context) *Context {
+	if base == nil {
+		base = c.goCtx
+	}
+	ctx, cancel := context.WithCancel(base)
+
+	child := &Context{
+		goCtx:      ctx,
+		cancel:     cancel,
+		parent:     c,
+		container:  NewContainer(c.container),
+		events:     c.Events(),
+		router:     c.Router(),
+		migrations: c.Migrations(),
+		tasks:      c.Tasks(),
+		schedules:  c.Schedules(),
+		settings:   c.Settings(),
+		values:     make(map[any]any),
+	}
+
+	c.mu.Lock()
+	c.children = append(c.children, child)
+	c.mu.Unlock()
+
+	return child
+}
+
+// Events returns the domain EventBus associated with this Context hierarchy.
+func (c *Context) Events() *EventBus {
+	return c.events
+}
+
+// Router returns the RouterExtension registry.
+func (c *Context) Router() extpoints.RouterExtension {
+	return c.router
+}
+
+// Migrations returns the MigrationExtension registry.
+func (c *Context) Migrations() extpoints.MigrationExtension {
+	return c.migrations
+}
+
+// Tasks returns the TaskExtension registry.
+func (c *Context) Tasks() extpoints.TaskExtension {
+	return c.tasks
+}
+
+// Task is an alias for Tasks().
+func (c *Context) Task() extpoints.TaskExtension {
+	return c.tasks
+}
+
+// Schedules returns the ScheduleExtension registry.
+func (c *Context) Schedules() extpoints.ScheduleExtension {
+	return c.schedules
+}
+
+// Schedule is an alias for Schedules().
+func (c *Context) Schedule() extpoints.ScheduleExtension {
+	return c.schedules
+}
+
+// Settings returns the SettingExtension registry.
+func (c *Context) Settings() extpoints.SettingExtension {
+	return c.settings
+}
+
+// Setting is an alias for Settings().
+func (c *Context) Setting() extpoints.SettingExtension {
+	return c.settings
+}
+
+// OnDispose registers a cleanup callback function to be executed when this Context is disposed.
+// It accepts func() error, func(), or Disposer.
+func (c *Context) OnDispose(fn any) {
+	if fn == nil {
+		return
+	}
+
+	var d Disposer
+	switch f := fn.(type) {
+	case Disposer:
+		d = f
+	case func() error:
+		d = f
+	case func():
+		d = func() error {
+			f()
+			return nil
+		}
+	default:
+		panic(fmt.Sprintf("core: OnDispose expects func() error or func(), got %T", fn))
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.disposers = append(c.disposers, d)
+}
+
+// Dispose shuts down this Context and all child Contexts, running registered disposers in LIFO order.
+func (c *Context) Dispose() error {
+	c.mu.Lock()
+	if c.disposed {
+		c.mu.Unlock()
+		return nil
+	}
+	c.disposed = true
+
+	// Copy children and disposers under lock
+	children := make([]*Context, len(c.children))
+	copy(children, c.children)
+
+	disposers := make([]Disposer, len(c.disposers))
+	copy(disposers, c.disposers)
+	c.mu.Unlock()
+
+	var errs []error
+
+	// 1. Dispose all child contexts in reverse order
+	for i := len(children) - 1; i >= 0; i-- {
+		if err := children[i].Dispose(); err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	// 2. Run local disposers in LIFO order
+	for i := len(disposers) - 1; i >= 0; i-- {
+		if err := disposers[i](); err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	// 3. Cancel the Go context
+	if c.cancel != nil {
+		c.cancel()
+	}
+
+	// 4. Detach from parent
+	if c.parent != nil {
+		c.parent.removeChild(c)
+	}
+
+	return errors.Join(errs...)
+}
+
+func (c *Context) removeChild(target *Context) {
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	for i, child := range c.children {
+		if child == target {
+			c.children = append(c.children[:i], c.children[i+1:]...)
+			break
+		}
+	}
+}
+
+// IsDisposed returns true if this Context has been disposed.
+func (c *Context) IsDisposed() bool {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+	return c.disposed
+}
+
+// RegisterDriver registers a runtime driver engine on this Context.
+func (c *Context) RegisterDriver(d Driver) error {
+	if d == nil {
+		return ErrNilService
+	}
+
+	c.mu.Lock()
+	defer c.mu.Unlock()
+	c.drivers = append(c.drivers, d)
+	return nil
+}
+
+// Drivers returns a copy of all drivers registered on this Context.
+func (c *Context) Drivers() []Driver {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	result := make([]Driver, len(c.drivers))
+	copy(result, c.drivers)
+	return result
+}
+
+// Driver looks up a registered driver by its driver type.
+func (c *Context) Driver(driverType DriverType) (Driver, bool) {
+	c.mu.RLock()
+	defer c.mu.RUnlock()
+
+	for _, d := range c.drivers {
+		if d.Type() == driverType {
+			return d, true
+		}
+	}
+	return nil, false
+}

backend/core/context_test.go

@@ -0,0 +1,502 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core_test
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/Rain-kl/Wavelet/backend/core"
+)
+
+// Sample services for testing
+type SampleService interface {
+	Greet(name string) string
+}
+
+type sampleServiceImpl struct {
+	prefix string
+}
+
+func (s *sampleServiceImpl) Greet(name string) string {
+	if s.prefix != "" {
+		return s.prefix + " " + name
+	}
+	return "Hello, " + name
+}
+
+type LogService interface {
+	Log(msg string)
+}
+
+type logServiceImpl struct {
+	logs []string
+}
+
+func (l *logServiceImpl) Log(msg string) {
+	l.logs = append(l.logs, msg)
+}
+
+type ConfigService interface {
+	Get(key string) string
+}
+
+type configServiceImpl struct {
+	data map[string]string
+}
+
+func (c *configServiceImpl) Get(key string) string {
+	return c.data[key]
+}
+
+// Sample plugin for testing
+type samplePlugin struct {
+	name string
+}
+
+func (p *samplePlugin) Name() string {
+	return p.name
+}
+
+func (p *samplePlugin) Apply(ctx *core.Context) error {
+	core.Provide[SampleService](ctx, &sampleServiceImpl{prefix: "Plugin:"})
+	return nil
+}
+
+func (p *samplePlugin) Manifest() core.Manifest {
+	return core.Manifest{
+		Name:        p.name,
+		Version:     "1.0.0",
+		Description: "Sample plugin",
+	}
+}
+
+// Sample driver for testing
+type mockDriver struct {
+	driverType core.DriverType
+	started    bool
+	stopped    bool
+}
+
+func (m *mockDriver) Type() core.DriverType {
+	return m.driverType
+}
+
+func (m *mockDriver) Start(ctx context.Context) error {
+	m.started = true
+	return nil
+}
+
+func (m *mockDriver) Stop(ctx context.Context) error {
+	m.stopped = true
+	return nil
+}
+
+func TestContextProvideAndInject(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+
+	// Before providing, Inject should fail
+	_, err := core.Inject[SampleService](ctx)
+	require.Error(t, err)
+	assert.True(t, errors.Is(err, core.ErrServiceNotFound))
+	assert.False(t, core.Has[SampleService](ctx))
+
+	// MustInject should panic
+	assert.Panics(t, func() {
+		core.MustInject[SampleService](ctx)
+	})
+
+	// Provide service
+	svcImpl := &sampleServiceImpl{prefix: "Hello,"}
+	core.Provide[SampleService](ctx, svcImpl)
+
+	// Inject should succeed
+	assert.True(t, core.Has[SampleService](ctx))
+	svc, err := core.Inject[SampleService](ctx)
+	require.NoError(t, err)
+	assert.Equal(t, "Hello, Wavelet", svc.Greet("Wavelet"))
+
+	// MustInject should succeed
+	mustSvc := core.MustInject[SampleService](ctx)
+	assert.Equal(t, "Hello, Cordis", mustSvc.Greet("Cordis"))
+}
+
+func TestContextProvideNilPanics(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+
+	assert.Panics(t, func() {
+		core.Provide[SampleService](nil, &sampleServiceImpl{})
+	})
+
+	assert.Panics(t, func() {
+		var nilSvc SampleService
+		core.Provide[SampleService](ctx, nilSvc)
+	})
+
+	assert.Panics(t, func() {
+		var nilImpl *sampleServiceImpl
+		core.Provide[*sampleServiceImpl](ctx, nilImpl)
+	})
+
+	// Inject with nil context
+	var nilCtx *core.Context
+	_, err := core.Inject[SampleService](nilCtx)
+	assert.ErrorIs(t, err, core.ErrNilContext)
+}
+
+func TestContextUsing(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+	var called bool
+
+	// Using when service not ready should return ErrServiceNotReady
+	err := core.Using(ctx, func(s SampleService) {
+		called = true
+		assert.Equal(t, "Hello, Cordis", s.Greet("Cordis"))
+	})
+	assert.Error(t, err)
+	assert.True(t, errors.Is(err, core.ErrServiceNotReady))
+	assert.False(t, called)
+
+	// Provide service and try Using again
+	core.Provide[SampleService](ctx, &sampleServiceImpl{})
+	err = core.Using(ctx, func(s SampleService) {
+		called = true
+		assert.Equal(t, "Hello, Cordis", s.Greet("Cordis"))
+	})
+	assert.NoError(t, err)
+	assert.True(t, called)
+}
+
+func TestContextUsingMultiple(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+
+	// Using2 with missing dependencies
+	var called2 bool
+	err := core.Using2(ctx, func(s SampleService, l LogService) {
+		called2 = true
+	})
+	assert.Error(t, err)
+	assert.False(t, called2)
+
+	// Provide 1 of 2
+	core.Provide[SampleService](ctx, &sampleServiceImpl{})
+	err = core.Using2(ctx, func(s SampleService, l LogService) {
+		called2 = true
+	})
+	assert.Error(t, err)
+	assert.False(t, called2)
+
+	// Provide 2 of 2
+	logSvc := &logServiceImpl{}
+	core.Provide[LogService](ctx, logSvc)
+	err = core.Using2(ctx, func(s SampleService, l LogService) {
+		called2 = true
+		l.Log(s.Greet("World"))
+	})
+	assert.NoError(t, err)
+	assert.True(t, called2)
+	assert.Equal(t, []string{"Hello, World"}, logSvc.logs)
+
+	// Using3 test - error condition
+	err = core.Using3(ctx, func(s SampleService, l LogService, c ConfigService) {})
+	assert.Error(t, err)
+
+	// Using3 test - success condition
+	var called3 bool
+	cfgSvc := &configServiceImpl{data: map[string]string{"env": "test"}}
+	core.Provide[ConfigService](ctx, cfgSvc)
+
+	err = core.Using3(ctx, func(s SampleService, l LogService, c ConfigService) {
+		called3 = true
+		assert.Equal(t, "test", c.Get("env"))
+	})
+	assert.NoError(t, err)
+	assert.True(t, called3)
+}
+
+func TestContextHierarchyAndFork(t *testing.T) {
+	parent := core.NewContext(nil) // nil base context test
+	core.Provide[SampleService](parent, &sampleServiceImpl{prefix: "Parent:"})
+
+	child := parent.ForkWithContext(nil) // nil child context test
+	require.NotNil(t, child)
+	assert.Equal(t, parent, child.Parent())
+
+	// Child can resolve service from parent
+	svc, err := core.Inject[SampleService](child)
+	require.NoError(t, err)
+	assert.Equal(t, "Parent: Ryan", svc.Greet("Ryan"))
+
+	// Child provides LogService
+	childLog := &logServiceImpl{}
+	core.Provide[LogService](child, childLog)
+
+	// Child has LogService, parent does not
+	assert.True(t, core.Has[LogService](child))
+	assert.False(t, core.Has[LogService](parent))
+
+	// Child overrides SampleService
+	core.Provide[SampleService](child, &sampleServiceImpl{prefix: "Child:"})
+	childSvc, err := core.Inject[SampleService](child)
+	require.NoError(t, err)
+	assert.Equal(t, "Child: Ryan", childSvc.Greet("Ryan"))
+
+	parentSvc, err := core.Inject[SampleService](parent)
+	require.NoError(t, err)
+	assert.Equal(t, "Parent: Ryan", parentSvc.Greet("Ryan"))
+}
+
+func TestContextReactiveWhen(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+
+	assert.Panics(t, func() {
+		core.When[SampleService](nil, func(s SampleService) {})
+	})
+
+	var whenCalled atomic.Bool
+	var greeted string
+
+	// Register When before service is provided
+	core.When[SampleService](ctx, func(s SampleService) {
+		whenCalled.Store(true)
+		greeted = s.Greet("Reactive")
+	})
+
+	assert.False(t, whenCalled.Load())
+
+	// Now Provide the service - listener should trigger
+	core.Provide[SampleService](ctx, &sampleServiceImpl{})
+
+	assert.True(t, whenCalled.Load())
+	assert.Equal(t, "Hello, Reactive", greeted)
+
+	// Register another When after service is already provided - should trigger immediately
+	var immediateCalled bool
+	core.When[SampleService](ctx, func(s SampleService) {
+		immediateCalled = true
+	})
+	assert.True(t, immediateCalled)
+}
+
+func TestContextDisposerLifecycle(t *testing.T) {
+	parent := core.NewContext(context.Background())
+	child := parent.Fork()
+
+	var order []string
+
+	// Test nil disposer
+	parent.OnDispose(nil)
+
+	// Test Disposer type
+	var customDisposer core.Disposer = func() error {
+		order = append(order, "parent-custom")
+		return nil
+	}
+	parent.OnDispose(customDisposer)
+
+	parent.OnDispose(func() error {
+		order = append(order, "parent-1")
+		return nil
+	})
+	parent.OnDispose(func() {
+		order = append(order, "parent-2")
+	})
+
+	child.OnDispose(func() error {
+		order = append(order, "child-1")
+		return errors.New("child-1 error")
+	})
+	child.OnDispose(func() {
+		order = append(order, "child-2")
+	})
+
+	assert.Panics(t, func() {
+		parent.OnDispose("invalid-func")
+	})
+
+	assert.False(t, parent.IsDisposed())
+	assert.False(t, child.IsDisposed())
+
+	// Disposing parent should cascade to children first, and execute disposers in LIFO order
+	err := parent.Dispose()
+	assert.Error(t, err) // child-1 error should be joined
+	assert.Contains(t, err.Error(), "child-1 error")
+
+	assert.True(t, parent.IsDisposed())
+	assert.True(t, child.IsDisposed())
+
+	// Child disposers run in LIFO: child-2, child-1
+	// Parent disposers run in LIFO: parent-2, parent-1, parent-custom
+	expected := []string{"child-2", "child-1", "parent-2", "parent-1", "parent-custom"}
+	assert.Equal(t, expected, order)
+
+	// Disposing again should be idempotent and return nil
+	err = parent.Dispose()
+	assert.NoError(t, err)
+}
+
+func TestContextStandardGoContext(t *testing.T) {
+	baseCtx, cancel := context.WithDeadline(context.Background(), time.Now().Add(5*time.Second))
+	defer cancel()
+
+	parentCtx := core.NewContext(baseCtx)
+	parentCtx.Set("parent_key", "parent_val")
+
+	childCtx := parentCtx.Fork()
+
+	// Deadline
+	dl, ok := childCtx.Deadline()
+	assert.True(t, ok)
+	assert.False(t, dl.IsZero())
+
+	// Value fallback: child has no key, falls back to parentCtx
+	assert.Equal(t, "parent_val", childCtx.Value("parent_key"))
+
+	// GoContext getter
+	assert.NotNil(t, childCtx.GoContext())
+
+	// Value not found in either
+	assert.Nil(t, childCtx.Value("non_existent_key"))
+
+	// Cancellation propagation
+	select {
+	case <-childCtx.Done():
+		t.Fatal("ctx should not be done yet")
+	default:
+	}
+
+	cancel()
+
+	select {
+	case <-childCtx.Done():
+		assert.Equal(t, context.Canceled, childCtx.Err())
+	case <-time.After(100 * time.Millisecond):
+		t.Fatal("ctx should be cancelled")
+	}
+}
+
+func TestManifestValidation(t *testing.T) {
+	mValid := core.Manifest{
+		Name:        "auth",
+		Version:     "1.0.0",
+		Description: "Auth plugin",
+	}
+	assert.NoError(t, mValid.Validate())
+
+	mInvalid := core.Manifest{
+		Version: "1.0.0",
+	}
+	assert.Error(t, mInvalid.Validate())
+}
+
+func TestDriverRegistration(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+
+	// Register nil driver returns error
+	assert.ErrorIs(t, ctx.RegisterDriver(nil), core.ErrNilService)
+
+	dHTTP := &mockDriver{driverType: core.DriverTypeHTTP}
+	dWorker := &mockDriver{driverType: core.DriverTypeWorker}
+
+	require.NoError(t, ctx.RegisterDriver(dHTTP))
+	require.NoError(t, ctx.RegisterDriver(dWorker))
+
+	drivers := ctx.Drivers()
+	assert.Len(t, drivers, 2)
+
+	foundHTTP, ok := ctx.Driver(core.DriverTypeHTTP)
+	assert.True(t, ok)
+	assert.Equal(t, dHTTP, foundHTTP)
+
+	foundWorker, ok := ctx.Driver(core.DriverTypeWorker)
+	assert.True(t, ok)
+	assert.Equal(t, dWorker, foundWorker)
+
+	_, ok = ctx.Driver(core.DriverTypeScheduler)
+	assert.False(t, ok)
+}
+
+func TestPluginInterfaces(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+	var p core.Plugin = &samplePlugin{name: "sample"}
+	assert.Equal(t, "sample", p.Name())
+	require.NoError(t, p.Apply(ctx))
+
+	svc, err := core.Inject[SampleService](ctx)
+	require.NoError(t, err)
+	assert.Equal(t, "Plugin: Ryan", svc.Greet("Ryan"))
+
+	var pwm core.PluginWithManifest = &samplePlugin{name: "sample"}
+	manifest := pwm.Manifest()
+	assert.Equal(t, "sample", manifest.Name)
+	assert.Equal(t, "1.0.0", manifest.Version)
+}
+
+func TestConcurrentAccess(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+	var wg sync.WaitGroup
+
+	// Concurrently provide, inject, fork, set, and get
+	for i := 0; i < 50; i++ {
+		wg.Add(1)
+		go func(idx int) {
+			defer wg.Done()
+			ctx.Set(fmt.Sprintf("key-%d", idx), idx)
+			_, _ = ctx.Get(fmt.Sprintf("key-%d", idx))
+
+			child := ctx.Fork()
+			child.Set("child_key", idx)
+		}(i)
+	}
+
+	core.Provide[SampleService](ctx, &sampleServiceImpl{})
+
+	for i := 0; i < 50; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			svc, err := core.Inject[SampleService](ctx)
+			if err == nil {
+				_ = svc.Greet("Concurrency")
+			}
+			_ = core.Using(ctx, func(s SampleService) {
+				_ = s.Greet("Safe")
+			})
+		}()
+	}
+
+	wg.Wait()
+}
+
+func TestContextExtensionPointsAccessors(t *testing.T) {
+	ctx := core.NewContext(nil)
+	assert.NotNil(t, ctx.Events())
+	assert.NotNil(t, ctx.Router())
+	assert.NotNil(t, ctx.Migrations())
+	assert.NotNil(t, ctx.Tasks())
+	assert.NotNil(t, ctx.Task())
+	assert.NotNil(t, ctx.Schedules())
+	assert.NotNil(t, ctx.Schedule())
+	assert.NotNil(t, ctx.Settings())
+	assert.NotNil(t, ctx.Setting())
+
+	child := ctx.Fork()
+	assert.Equal(t, ctx.Events(), child.Events())
+	assert.Equal(t, ctx.Router(), child.Router())
+	assert.Equal(t, ctx.Migrations(), child.Migrations())
+	assert.Equal(t, ctx.Tasks(), child.Tasks())
+	assert.Equal(t, ctx.Task(), child.Task())
+	assert.Equal(t, ctx.Schedules(), child.Schedules())
+	assert.Equal(t, ctx.Schedule(), child.Schedule())
+	assert.Equal(t, ctx.Settings(), child.Settings())
+	assert.Equal(t, ctx.Setting(), child.Setting())
+}

backend/core/contracts/auth.go

@@ -0,0 +1,100 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package contracts defines unified service interfaces and DTOs for cross-plugin communication.
+package contracts
+
+import (
+	"context"
+	"time"
+)
+
+// UserDTO represents a unified user data transfer object across plugins.
+type UserDTO struct {
+	ID                 uint64    `json:"id,string"`
+	Username           string    `json:"username"`
+	Nickname           string    `json:"nickname"`
+	Email              string    `json:"email"`
+	AvatarURL          string    `json:"avatar_url"`
+	IsActive           bool      `json:"is_active"`
+	IsAdmin            bool      `json:"is_admin"`
+	NeedChangePassword bool      `json:"need_change_password,omitempty"`
+	Bio                string    `json:"bio,omitempty"`
+	Phone              string    `json:"phone,omitempty"`
+	Gender             string    `json:"gender,omitempty"`
+	Website            string    `json:"website,omitempty"`
+	Location           string    `json:"location,omitempty"`
+	LastLoginAt        time.Time `json:"last_login_at"`
+	CreatedAt          time.Time `json:"created_at"`
+	UpdatedAt          time.Time `json:"updated_at"`
+}
+
+// TableName returns w_users.
+func (UserDTO) TableName() string {
+	return "w_users"
+}
+
+// OAuthUserInfoDTO contains user identity claims obtained from an OAuth provider.
+type OAuthUserInfoDTO struct {
+	ID                uint64 `json:"id"`
+	Sub               string `json:"sub"`
+	Username          string `json:"username"`
+	PreferredUsername string `json:"preferred_username"`
+	Email             string `json:"email"`
+	Name              string `json:"name"`
+	Active            bool   `json:"active"`
+	AvatarURL         string `json:"avatar_url"`
+}
+
+// OAuthProvider defines the pluggable OAuth provider contract.
+type OAuthProvider interface {
+	Name() string
+	GetAuthURL(state string) string
+	ExchangeCode(ctx context.Context, code string) (*OAuthUserInfoDTO, error)
+}
+
+// AuthService defines the contract for authentication, session verification, and token management.
+type AuthService interface {
+	// RequireAuthMiddleware returns a middleware handler (compatible with gin.HandlerFunc or standard middleware).
+	RequireAuthMiddleware() any
+
+	// RequireAdminMiddleware returns an admin authorization middleware.
+	RequireAdminMiddleware() any
+
+	// GetCurrentUser retrieves the authenticated UserDTO from context.
+	GetCurrentUser(ctx context.Context) (*UserDTO, error)
+
+	// GetCurrentUserID retrieves the authenticated user ID from session/context.
+	GetCurrentUserID(ctx context.Context) (uint64, error)
+
+	// VerifyToken validates an access token and returns the associated user DTO.
+	VerifyToken(ctx context.Context, token string) (*UserDTO, error)
+
+	// CreateSession establishes an authenticated session for the given user ID.
+	CreateSession(ctx context.Context, userID uint64, extras map[string]any) (string, error)
+
+	// RevokeToken invalidates a specific access token by its hash.
+	RevokeToken(ctx context.Context, tokenHash string) error
+
+	// RevokeUserSessions revokes all active sessions and cached tokens for a user.
+	RevokeUserSessions(ctx context.Context, userID uint64) error
+
+	// DisallowTokenAuthMiddleware returns a middleware that rejects requests authenticated via access token.
+	DisallowTokenAuthMiddleware() any
+}
+
+// AuthRegistry allows downstream and domain plugins to register custom authentication providers.
+type AuthRegistry interface {
+	RegisterOAuthProvider(name string, provider OAuthProvider)
+	GetOAuthProvider(name string) (OAuthProvider, bool)
+	ListOAuthProviders() []string
+}
+
+// Auth context keys — stored in Gin context by auth middleware, consumed by domain plugins.
+const (
+	AuthUserIDKey     = "user_id"
+	AuthUserNameKey   = "username"
+	AuthUserObjKey    = "user_obj"
+	AuthTokenAuthKey  = "token_auth"  // marks if request uses access token auth
+	AuthTokenAdminKey = "token_admin" // whether the access token has admin privileges
+)

backend/core/contracts/cache.go

@@ -0,0 +1,32 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package contracts defines unified service interfaces and DTOs for cross-plugin communication.
+package contracts
+
+import (
+	"context"
+	"errors"
+	"time"
+)
+
+// ErrCacheMiss is returned when an item is not found in the cache.
+var ErrCacheMiss = errors.New("contracts/cache: key not found")
+
+// CacheService defines the contract for multi-layer cache operations (RAM L1 + Redis L2 + Pub/Sub invalidation).
+type CacheService interface {
+	// Get retrieves an item from cache into target. Returns ErrCacheMiss if not found.
+	Get(ctx context.Context, key string, target any) error
+
+	// Set stores an item into cache with a specified time-to-live duration.
+	Set(ctx context.Context, key string, value any, ttl time.Duration) error
+
+	// Delete evicts a key from local and remote cache tiers and broadcasts invalidation.
+	Delete(ctx context.Context, key string) error
+
+	// GetOrSet retrieves an item from cache, or calls loader to populate and return if missing.
+	GetOrSet(ctx context.Context, key string, target any, ttl time.Duration, loader func() (any, error)) error
+
+	// Invalidate is a semantic alias for Delete.
+	Invalidate(ctx context.Context, key string) error
+}

backend/core/contracts/database.go

@@ -0,0 +1,23 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package contracts defines unified service interfaces and DTOs for cross-plugin communication.
+package contracts
+
+import (
+	"context"
+
+	"gorm.io/gorm"
+)
+
+// DBService defines the standard contract for relational database access and multi-datasource routing.
+type DBService interface {
+	// GORM returns the underlying GORM database instance.
+	GORM() *gorm.DB
+
+	// DB returns the GORM database instance bound to the given context.
+	DB(ctx context.Context) *gorm.DB
+
+	// Named returns a named database connection if multiple data sources or replicas are configured.
+	Named(name string) *gorm.DB
+}

backend/core/contracts/events.go

@@ -0,0 +1,109 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package contracts defines unified service interfaces and DTOs for cross-plugin communication.
+package contracts
+
+// ======================================================================
+// Domain Event Topic Constants
+// ======================================================================
+//
+// All cross-plugin domain event topics MUST be declared here so that
+// producers and consumers share the same string values without importing
+// each other's implementation packages.
+// ======================================================================
+
+// --- Auth & User Events ---
+const (
+	// EventTopicAdminLoggedIn fires when an admin user logs in.
+	EventTopicAdminLoggedIn = "admin:logged_in"
+
+	// EventTopicUserCreated fires when a new user account is created.
+	EventTopicUserCreated = "user:created"
+
+	// EventTopicUserUpdated fires when a user profile is updated.
+	EventTopicUserUpdated = "user:updated"
+
+	// EventTopicUserDeleted fires when a user account is deleted.
+	EventTopicUserDeleted = "user:deleted"
+)
+
+// --- Admin & System Events ---
+const (
+	// EventTopicConfigChanged fires when a system configuration value changes.
+	EventTopicConfigChanged = "admin:config_changed"
+
+	// EventTopicSystemCleanup fires when a periodic system cleanup completes.
+	EventTopicSystemCleanup = "admin:system_cleanup"
+)
+
+// --- Upload / Storage Events ---
+const (
+	// EventTopicUploadCreated fires when a new file upload is recorded.
+	EventTopicUploadCreated = "upload:created"
+
+	// EventTopicUploadDeleted fires when a file upload is removed.
+	EventTopicUploadDeleted = "upload:deleted"
+
+	// EventTopicIngestComplete fires when a programmatic file ingest finishes.
+	EventTopicIngestComplete = "upload:ingest_complete"
+)
+
+// --- Message Gateway Events ---
+const (
+	// EventTopicNotificationSent fires when a push notification is dispatched.
+	EventTopicNotificationSent = "message:notification_sent"
+
+	// EventTopicChannelBound fires when a user binds a messaging channel.
+	EventTopicChannelBound = "message:channel_bound"
+
+	// EventTopicChannelUnbound fires when a user unbinds a messaging channel.
+	EventTopicChannelUnbound = "message:channel_unbound"
+)
+
+// --- Risk Control Events ---
+const (
+	// EventTopicAccessLogRecorded fires when a user access log entry is recorded.
+	EventTopicAccessLogRecorded = "risk:access_log_recorded"
+)
+
+// ======================================================================
+// Domain Event Payload DTOs
+// ======================================================================
+
+// AdminLoggedIn 管理员登录领域事件载荷
+type AdminLoggedIn struct {
+	User *UserDTO `json:"user"`
+	IP   string   `json:"ip"`
+}
+
+// UserCreatedEvent fires when a new user account is created.
+type UserCreatedEvent struct {
+	User     *UserDTO `json:"user"`
+	Password string   `json:"-"`
+}
+
+// ConfigChangedEvent fires when a system configuration value changes.
+type ConfigChangedEvent struct {
+	Key    string `json:"key"`
+	OldVal any    `json:"old_val,omitempty"`
+	NewVal any    `json:"new_val,omitempty"`
+}
+
+// UploadCreatedEvent fires when a new file upload is recorded.
+type UploadCreatedEvent struct {
+	UploadID uint64 `json:"upload_id,string"`
+	UserID   uint64 `json:"user_id,string"`
+	FileName string `json:"file_name"`
+	FileSize int64  `json:"file_size"`
+	MimeType string `json:"mime_type"`
+}
+
+// NotificationSentEvent fires when a push notification is dispatched.
+type NotificationSentEvent struct {
+	UserID    uint64 `json:"user_id,string"`
+	Channel   string `json:"channel"`
+	Title     string `json:"title"`
+	Success   bool   `json:"success"`
+	ErrorInfo string `json:"error_info,omitempty"`
+}

backend/core/contracts/logger.go

@@ -0,0 +1,39 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package contracts defines unified service interfaces and DTOs for cross-plugin communication.
+package contracts
+
+import (
+	"context"
+)
+
+// LoggerService defines the contract for structured logging with trace ID and context correlation.
+type LoggerService interface {
+	// Debug logs a debug message with optional key-value structured fields.
+	Debug(ctx context.Context, msg string, keysAndValues ...any)
+
+	// Info logs an informational message with optional key-value structured fields.
+	Info(ctx context.Context, msg string, keysAndValues ...any)
+
+	// Warn logs a warning message with optional key-value structured fields.
+	Warn(ctx context.Context, msg string, keysAndValues ...any)
+
+	// Error logs an error message with optional key-value structured fields.
+	Error(ctx context.Context, msg string, keysAndValues ...any)
+
+	// Debugf logs a formatted debug message.
+	Debugf(ctx context.Context, format string, args ...any)
+
+	// Infof logs a formatted informational message.
+	Infof(ctx context.Context, format string, args ...any)
+
+	// Warnf logs a formatted warning message.
+	Warnf(ctx context.Context, format string, args ...any)
+
+	// Errorf logs a formatted error message.
+	Errorf(ctx context.Context, format string, args ...any)
+
+	// With returns a child logger enriched with additional key-value attributes.
+	With(keysAndValues ...any) LoggerService
+}

backend/core/contracts/storage.go

@@ -0,0 +1,62 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package contracts defines unified service interfaces and DTOs for cross-plugin communication.
+package contracts
+
+import (
+	"context"
+	"io"
+)
+
+// StorageObject represents a retrieved file object from the storage backend.
+type StorageObject struct {
+	Key           string
+	CachePath     string
+	Body          io.ReadCloser
+	ContentLength int64
+	ContentType   string
+}
+
+// StoragePutResult describes the output of a successful Put operation.
+type StoragePutResult struct {
+	Key    string
+	Bucket string
+}
+
+// IngestOptions configures programmatic ingest of files into the platform storage.
+type IngestOptions struct {
+	UserID    uint64
+	Type      string
+	FileName  string
+	MimeType  string
+	Extension string
+	Size      int64
+	Policy    int
+	Metadata  map[string]any
+}
+
+// IngestResult reports the outcome of a programmatic file ingest operation.
+type IngestResult struct {
+	ID       uint64
+	Key      string
+	URL      string
+	Created  bool
+	Stored   bool
+	Resolved bool
+}
+
+// StorageService defines the contract for unified object storage and managed file ingestion.
+type StorageService interface {
+	// Put writes an object to storage.
+	Put(ctx context.Context, key string, body io.Reader, size int64, contentType string) (StoragePutResult, error)
+
+	// Get retrieves an object from storage.
+	Get(ctx context.Context, key string) (*StorageObject, error)
+
+	// Delete removes an object from storage.
+	Delete(ctx context.Context, key string) error
+
+	// Ingest performs managed file ingestion into the platform storage domain with deduplication and metadata tracking.
+	Ingest(ctx context.Context, reader io.Reader, opts IngestOptions) (*IngestResult, error)
+}

backend/core/contracts/user.go

@@ -0,0 +1,84 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package contracts defines unified service interfaces and DTOs for cross-plugin communication.
+package contracts
+
+import (
+	"context"
+)
+
+// CreateUserRequest contains fields to register or create a new user.
+type CreateUserRequest struct {
+	Username string `json:"username"`
+	Password string `json:"password"`
+	Nickname string `json:"nickname"`
+	Email    string `json:"email"`
+	IsAdmin  bool   `json:"is_admin"`
+}
+
+// UpdateUserProfileRequest contains fields for updating a user's profile.
+type UpdateUserProfileRequest struct {
+	Nickname  *string `json:"nickname,omitempty"`
+	Email     *string `json:"email,omitempty"`
+	AvatarURL *string `json:"avatar_url,omitempty"`
+	Bio       *string `json:"bio,omitempty"`
+	Phone     *string `json:"phone,omitempty"`
+	Gender    *string `json:"gender,omitempty"`
+	Website   *string `json:"website,omitempty"`
+	Location  *string `json:"location,omitempty"`
+}
+
+// UserService defines the contract for user account management and profile queries.
+type UserService interface {
+	// GetUserByID retrieves a user by ID.
+	GetUserByID(ctx context.Context, id uint64) (*UserDTO, error)
+
+	// GetUserByUsername retrieves a user by username.
+	GetUserByUsername(ctx context.Context, username string) (*UserDTO, error)
+
+	// GetUserByEmail retrieves a user by email.
+	GetUserByEmail(ctx context.Context, email string) (*UserDTO, error)
+
+	// CreateUser registers or creates a new user account.
+	CreateUser(ctx context.Context, req CreateUserRequest) (*UserDTO, error)
+
+	// UpdateProfile updates the profile of the specified user.
+	UpdateProfile(ctx context.Context, id uint64, req UpdateUserProfileRequest) (*UserDTO, error)
+
+	// UpdatePassword updates the password for the specified user after verifying the old password.
+	UpdatePassword(ctx context.Context, id uint64, oldPassword, newPassword string) error
+
+	// VerifyPassword verifies if the given password matches the user's password.
+	VerifyPassword(ctx context.Context, id uint64, password string) bool
+
+	// UpdateLastLogin updates the user's last login timestamp.
+	UpdateLastLogin(ctx context.Context, id uint64, ip string) error
+
+	// ListUsers returns a paginated list of users with optional keyword search.
+	ListUsers(ctx context.Context, page, pageSize int, keyword string) ([]*UserDTO, int64, error)
+
+	// SetUserActive sets the active/banned status for a user.
+	SetUserActive(ctx context.Context, id uint64, active bool) error
+
+	// SetUserAdmin sets the admin role status for a user.
+	SetUserAdmin(ctx context.Context, id uint64, admin bool) error
+
+	// VerifyAccessToken verifies an access token hash and returns the user DTO and isAdmin flag.
+	VerifyAccessToken(ctx context.Context, tokenHash string) (*UserDTO, bool, error)
+
+	// DeleteUser removes a user and related access tokens.
+	DeleteUser(ctx context.Context, id uint64) error
+
+	// CountUsers returns total user count.
+	CountUsers(ctx context.Context) (int64, error)
+
+	// CountActiveUsers returns active user count.
+	CountActiveUsers(ctx context.Context) (int64, error)
+
+	// GetFirstAdminUser returns the earliest admin user.
+	GetFirstAdminUser(ctx context.Context) (*UserDTO, error)
+
+	// UniqueUsername generates a unique username candidate based on base.
+	UniqueUsername(ctx context.Context, base string) (string, error)
+}

backend/core/events.go

@@ -0,0 +1,278 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"reflect"
+	"sync"
+	"sync/atomic"
+)
+
+const maxHandlerParams = 2
+
+var ctxInterfaceType = reflect.TypeFor[context.Context]()
+var errInterfaceType = reflect.TypeFor[error]()
+
+type eventListener struct {
+	id         uint64
+	fnVal      reflect.Value
+	numIn      int
+	hasCtx     bool
+	hasPayload bool
+	argType    reflect.Type
+	returnsErr bool
+}
+
+// EventBus is a thread-safe, strongly-typed in-process domain event bus.
+type EventBus struct {
+	mu       sync.RWMutex
+	nextID   atomic.Uint64
+	handlers map[string][]eventListener
+}
+
+// NewEventBus creates a new EventBus instance.
+func NewEventBus() *EventBus {
+	return &EventBus{
+		handlers: make(map[string][]eventListener),
+	}
+}
+
+// On registers an event handler for the given topic.
+//
+// Supported handler signatures:
+//   - func(ctx context.Context, event T) error
+//   - func(ctx context.Context, event T)
+//   - func(event T) error
+//   - func(event T)
+//   - func(ctx context.Context) error
+//   - func(ctx context.Context)
+//   - func() error
+//   - func()
+//
+// Returns a Disposer function that unregisters the handler when called.
+func (b *EventBus) On(topic string, handler any) Disposer {
+	if handler == nil {
+		panic("core/events: handler cannot be nil")
+	}
+
+	fnVal := reflect.ValueOf(handler)
+	fnType := fnVal.Type()
+
+	if fnType.Kind() != reflect.Func {
+		panic(fmt.Sprintf("core/events: expected func, got %s", fnType.Kind()))
+	}
+
+	numIn := fnType.NumIn()
+	if numIn > maxHandlerParams {
+		panic(fmt.Sprintf("core/events: handler has %d parameters, maximum 2 supported (ctx, event)", numIn))
+	}
+
+	numOut := fnType.NumOut()
+	if numOut > 1 {
+		panic(fmt.Sprintf("core/events: handler has %d return values, maximum 1 supported (error)", numOut))
+	}
+
+	returnsErr := false
+	if numOut == 1 {
+		outType := fnType.Out(0)
+		if !outType.Implements(errInterfaceType) {
+			panic(fmt.Sprintf("core/events: handler return type must be error, got %v", outType))
+		}
+		returnsErr = true
+	}
+
+	listener := eventListener{
+		id:         b.nextID.Add(1),
+		fnVal:      fnVal,
+		numIn:      numIn,
+		returnsErr: returnsErr,
+	}
+
+	switch numIn {
+	case 0:
+		// func() or func() error
+	case 1:
+		in0 := fnType.In(0)
+		if in0.Implements(ctxInterfaceType) {
+			listener.hasCtx = true
+		} else {
+			listener.hasPayload = true
+			listener.argType = in0
+		}
+	case 2:
+		in0 := fnType.In(0)
+		if !in0.Implements(ctxInterfaceType) {
+			panic(fmt.Sprintf("core/events: first parameter must implement context.Context, got %v", in0))
+		}
+		listener.hasCtx = true
+		listener.hasPayload = true
+		listener.argType = fnType.In(1)
+	}
+
+	b.mu.Lock()
+	b.handlers[topic] = append(b.handlers[topic], listener)
+	b.mu.Unlock()
+
+	listenerID := listener.id
+	var disposed atomic.Bool
+
+	return func() error {
+		if disposed.Swap(true) {
+			return nil
+		}
+
+		b.mu.Lock()
+		defer b.mu.Unlock()
+
+		list := b.handlers[topic]
+		for i, l := range list {
+			if l.id == listenerID {
+				b.handlers[topic] = append(list[:i], list[i+1:]...)
+				break
+			}
+		}
+
+		if len(b.handlers[topic]) == 0 {
+			delete(b.handlers, topic)
+		}
+
+		return nil
+	}
+}
+
+// Subscribe registers a strongly-typed generic event listener on the given EventBus.
+func Subscribe[T any](bus *EventBus, topic string, handler func(ctx context.Context, event T) error) Disposer {
+	if bus == nil {
+		panic("core/events: nil EventBus provided to Subscribe")
+	}
+	return bus.On(topic, handler)
+}
+
+// Emit publishes an event to all subscribers of the specified topic.
+// Handlers are executed synchronously. If any handler panics or returns an error,
+// the error is collected and returned via errors.Join.
+//
+//nolint:contextcheck
+func (b *EventBus) Emit(ctx context.Context, topic string, payload any) error {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	b.mu.RLock()
+	rawListeners := b.handlers[topic]
+	if len(rawListeners) == 0 {
+		b.mu.RUnlock()
+		return nil
+	}
+
+	listeners := make([]eventListener, len(rawListeners))
+	copy(listeners, rawListeners)
+	b.mu.RUnlock()
+
+	var payloadVal reflect.Value
+	if payload != nil {
+		payloadVal = reflect.ValueOf(payload)
+	}
+
+	var errs []error
+	for _, l := range listeners {
+		args := b.buildArgs(ctx, l, payloadVal)
+
+		err := func() (resErr error) {
+			defer func() {
+				if r := recover(); r != nil {
+					resErr = fmt.Errorf("core/events: panic in handler for topic %q: %v", topic, r)
+				}
+			}()
+
+			results := l.fnVal.Call(args)
+			if l.returnsErr && len(results) > 0 && !results[0].IsNil() {
+				resErr = results[0].Interface().(error)
+			}
+			return resErr
+		}()
+
+		if err != nil {
+			errs = append(errs, err)
+		}
+	}
+
+	return errors.Join(errs...)
+}
+
+func (b *EventBus) buildArgs(ctx context.Context, l eventListener, payloadVal reflect.Value) []reflect.Value {
+	if l.numIn == 0 {
+		return nil
+	}
+
+	args := make([]reflect.Value, 0, l.numIn)
+	if l.hasCtx {
+		args = append(args, reflect.ValueOf(ctx))
+	}
+
+	if l.hasPayload {
+		arg := b.convertPayload(payloadVal, l.argType)
+		args = append(args, arg)
+	}
+
+	return args
+}
+
+func (b *EventBus) convertPayload(payloadVal reflect.Value, targetType reflect.Type) reflect.Value {
+	if !payloadVal.IsValid() {
+		return reflect.Zero(targetType)
+	}
+
+	valType := payloadVal.Type()
+
+	// 1. Direct assignable
+	if valType.AssignableTo(targetType) {
+		return payloadVal
+	}
+
+	// 2. Direct convertible
+	if valType.ConvertibleTo(targetType) {
+		return payloadVal.Convert(targetType)
+	}
+
+	// 3. Payload is pointer *T, target expects T
+	if valType.Kind() == reflect.Pointer && valType.Elem().AssignableTo(targetType) {
+		if !payloadVal.IsNil() {
+			return payloadVal.Elem()
+		}
+		return reflect.Zero(targetType)
+	}
+
+	// 4. Payload is value T, target expects *T
+	if targetType.Kind() == reflect.Pointer && valType.AssignableTo(targetType.Elem()) {
+		ptr := reflect.New(valType)
+		ptr.Elem().Set(payloadVal)
+		return ptr
+	}
+
+	// Fallback to zero value of targetType
+	return reflect.Zero(targetType)
+}
+
+// Listeners returns the number of active listeners for a topic.
+func (b *EventBus) Listeners(topic string) int {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+	return len(b.handlers[topic])
+}
+
+// Topics returns all topics that have registered listeners.
+func (b *EventBus) Topics() []string {
+	b.mu.RLock()
+	defer b.mu.RUnlock()
+
+	topics := make([]string, 0, len(b.handlers))
+	for t := range b.handlers {
+		topics = append(topics, t)
+	}
+	return topics
+}

backend/core/events_test.go

@@ -0,0 +1,318 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core_test
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/Rain-kl/Wavelet/backend/core"
+)
+
+type UserRegisteredEvent struct {
+	UserID   string `json:"user_id"`
+	Username string `json:"username"`
+}
+
+type OrderCreatedEvent struct {
+	OrderID string  `json:"order_id"`
+	Amount  float64 `json:"amount"`
+}
+
+func TestEventBusPublishSubscribe(t *testing.T) {
+	bus := core.NewEventBus()
+	var receivedID string
+
+	disposer := bus.On("user:registered", func(ctx context.Context, e UserRegisteredEvent) error {
+		receivedID = e.UserID
+		return nil
+	})
+	require.NotNil(t, disposer)
+
+	assert.Equal(t, []string{"user:registered"}, bus.Topics())
+
+	err := bus.Emit(context.Background(), "user:registered", UserRegisteredEvent{UserID: "u_999", Username: "alice"})
+	assert.NoError(t, err)
+	assert.Equal(t, "u_999", receivedID)
+
+	// Emit to empty topic returns nil error
+	err = bus.Emit(nil, "empty:topic", nil)
+	assert.NoError(t, err)
+}
+
+func TestEventBusGenericSubscribe(t *testing.T) {
+	bus := core.NewEventBus()
+	var receivedOrder string
+
+	assert.Panics(t, func() {
+		core.Subscribe[OrderCreatedEvent](nil, "order:created", func(ctx context.Context, e OrderCreatedEvent) error {
+			return nil
+		})
+	})
+
+	disposer := core.Subscribe(bus, "order:created", func(ctx context.Context, e OrderCreatedEvent) error {
+		receivedOrder = e.OrderID
+		return nil
+	})
+	require.NotNil(t, disposer)
+
+	err := bus.Emit(context.Background(), "order:created", OrderCreatedEvent{OrderID: "ord_123", Amount: 99.5})
+	assert.NoError(t, err)
+	assert.Equal(t, "ord_123", receivedOrder)
+
+	// Test unsubscribe via disposer
+	err = disposer()
+	assert.NoError(t, err)
+
+	receivedOrder = ""
+	err = bus.Emit(context.Background(), "order:created", OrderCreatedEvent{OrderID: "ord_456", Amount: 100})
+	assert.NoError(t, err)
+	assert.Empty(t, receivedOrder, "handler should not be called after disposal")
+}
+
+func TestEventBusHandlerSignatures(t *testing.T) {
+	bus := core.NewEventBus()
+
+	var (
+		calledWithCtxPayloadErr atomic.Bool
+		calledWithCtxPayload    atomic.Bool
+		calledWithPayloadErr    atomic.Bool
+		calledWithPayload       atomic.Bool
+		calledWithCtxErr        atomic.Bool
+		calledWithCtx           atomic.Bool
+		calledWithNoArgsErr     atomic.Bool
+		calledWithNoArgs        atomic.Bool
+	)
+
+	bus.On("test:sig", func(ctx context.Context, e UserRegisteredEvent) error {
+		calledWithCtxPayloadErr.Store(true)
+		assert.Equal(t, "u_1", e.UserID)
+		return nil
+	})
+
+	bus.On("test:sig", func(ctx context.Context, e UserRegisteredEvent) {
+		calledWithCtxPayload.Store(true)
+		assert.Equal(t, "u_1", e.UserID)
+	})
+
+	bus.On("test:sig", func(e UserRegisteredEvent) error {
+		calledWithPayloadErr.Store(true)
+		assert.Equal(t, "u_1", e.UserID)
+		return nil
+	})
+
+	bus.On("test:sig", func(e UserRegisteredEvent) {
+		calledWithPayload.Store(true)
+		assert.Equal(t, "u_1", e.UserID)
+	})
+
+	bus.On("test:sig", func(ctx context.Context) error {
+		calledWithCtxErr.Store(true)
+		return nil
+	})
+
+	bus.On("test:sig", func(ctx context.Context) {
+		calledWithCtx.Store(true)
+	})
+
+	bus.On("test:sig", func() error {
+		calledWithNoArgsErr.Store(true)
+		return nil
+	})
+
+	bus.On("test:sig", func() {
+		calledWithNoArgs.Store(true)
+	})
+
+	err := bus.Emit(context.Background(), "test:sig", UserRegisteredEvent{UserID: "u_1", Username: "test"})
+	assert.NoError(t, err)
+
+	assert.True(t, calledWithCtxPayloadErr.Load())
+	assert.True(t, calledWithCtxPayload.Load())
+	assert.True(t, calledWithPayloadErr.Load())
+	assert.True(t, calledWithPayload.Load())
+	assert.True(t, calledWithCtxErr.Load())
+	assert.True(t, calledWithCtx.Load())
+	assert.True(t, calledWithNoArgsErr.Load())
+	assert.True(t, calledWithNoArgs.Load())
+}
+
+func TestEventBusPointerAndValueConversion(t *testing.T) {
+	bus := core.NewEventBus()
+
+	var (
+		receivedFromValueToPtr atomic.Bool
+		receivedFromPtrToValue atomic.Bool
+		receivedFromNilPtr     atomic.Bool
+	)
+
+	// Handler expects pointer, payload emitted as value
+	bus.On("test:ptr", func(ctx context.Context, e *UserRegisteredEvent) error {
+		if e != nil && e.UserID == "u_ptr" {
+			receivedFromValueToPtr.Store(true)
+		}
+		return nil
+	})
+
+	err := bus.Emit(context.Background(), "test:ptr", UserRegisteredEvent{UserID: "u_ptr"})
+	assert.NoError(t, err)
+	assert.True(t, receivedFromValueToPtr.Load())
+
+	// Handler expects value, payload emitted as pointer
+	bus.On("test:val", func(ctx context.Context, e UserRegisteredEvent) error {
+		if e.UserID == "u_val" {
+			receivedFromPtrToValue.Store(true)
+		}
+		return nil
+	})
+
+	err = bus.Emit(context.Background(), "test:val", &UserRegisteredEvent{UserID: "u_val"})
+	assert.NoError(t, err)
+	assert.True(t, receivedFromPtrToValue.Load())
+
+	// Handler expects value, payload is nil pointer
+	var nilEvent *UserRegisteredEvent
+	bus.On("test:nil_ptr", func(ctx context.Context, e UserRegisteredEvent) error {
+		assert.Equal(t, "", e.UserID)
+		receivedFromNilPtr.Store(true)
+		return nil
+	})
+	err = bus.Emit(context.Background(), "test:nil_ptr", nilEvent)
+	assert.NoError(t, err)
+	assert.True(t, receivedFromNilPtr.Load())
+
+	// Convertible type test (int to int64)
+	var receivedConvert int64
+	bus.On("test:conv", func(e int64) {
+		receivedConvert = e
+	})
+	err = bus.Emit(context.Background(), "test:conv", int(42))
+	assert.NoError(t, err)
+	assert.Equal(t, int64(42), receivedConvert)
+}
+
+func TestEventBusErrorCollectionAndPanicRecovery(t *testing.T) {
+	bus := core.NewEventBus()
+
+	errHandler1 := errors.New("handler 1 failed")
+	errHandler2 := errors.New("handler 2 failed")
+
+	bus.On("test:err", func() error {
+		return errHandler1
+	})
+
+	bus.On("test:err", func() {
+		panic("something went horribly wrong")
+	})
+
+	bus.On("test:err", func() error {
+		return errHandler2
+	})
+
+	err := bus.Emit(context.Background(), "test:err", nil)
+	require.Error(t, err)
+	assert.True(t, errors.Is(err, errHandler1) || errors.Is(err, errHandler2))
+	assert.Contains(t, err.Error(), "handler 1 failed")
+	assert.Contains(t, err.Error(), "handler 2 failed")
+	assert.Contains(t, err.Error(), "panic")
+}
+
+func TestEventBusInvalidHandlerPanics(t *testing.T) {
+	bus := core.NewEventBus()
+
+	assert.Panics(t, func() {
+		bus.On("test:invalid", nil)
+	})
+
+	assert.Panics(t, func() {
+		bus.On("test:invalid", "not-a-func")
+	})
+
+	assert.Panics(t, func() {
+		// More than 2 arguments
+		bus.On("test:invalid", func(a, b, c string) {})
+	})
+
+	assert.Panics(t, func() {
+		// 2 args, but first is not context
+		bus.On("test:invalid", func(a string, b int) {})
+	})
+
+	assert.Panics(t, func() {
+		// More than 1 return value
+		bus.On("test:invalid", func() (int, error) { return 0, nil })
+	})
+
+	assert.Panics(t, func() {
+		// Return value is not error
+		bus.On("test:invalid", func() int { return 0 })
+	})
+}
+
+func TestEventBusListenersCountAndDisposerIdempotence(t *testing.T) {
+	bus := core.NewEventBus()
+
+	assert.Equal(t, 0, bus.Listeners("topic1"))
+
+	d1 := bus.On("topic1", func() {})
+	d2 := bus.On("topic1", func() {})
+	assert.Equal(t, 2, bus.Listeners("topic1"))
+
+	_ = d1()
+	assert.Equal(t, 1, bus.Listeners("topic1"))
+
+	// Calling disposer again should be no-op
+	_ = d1()
+	assert.Equal(t, 1, bus.Listeners("topic1"))
+
+	_ = d2()
+	assert.Equal(t, 0, bus.Listeners("topic1"))
+}
+
+func TestEventBusConcurrentAccess(t *testing.T) {
+	bus := core.NewEventBus()
+	var wg sync.WaitGroup
+
+	var receivedCount atomic.Int64
+
+	// Concurrently subscribe and emit
+	for i := 0; i < 50; i++ {
+		wg.Add(1)
+		go func(idx int) {
+			defer wg.Done()
+			topic := fmt.Sprintf("topic:%d", idx%5)
+			disposer := bus.On(topic, func(ctx context.Context, e UserRegisteredEvent) error {
+				receivedCount.Add(1)
+				return nil
+			})
+
+			// Emit some events
+			_ = bus.Emit(context.Background(), topic, UserRegisteredEvent{UserID: fmt.Sprintf("u_%d", idx)})
+
+			// Randomly dispose
+			if idx%2 == 0 {
+				_ = disposer()
+			}
+		}(i)
+	}
+
+	for i := 0; i < 50; i++ {
+		wg.Add(1)
+		go func(idx int) {
+			defer wg.Done()
+			topic := fmt.Sprintf("topic:%d", idx%5)
+			_ = bus.Emit(context.Background(), topic, UserRegisteredEvent{UserID: fmt.Sprintf("u_%d", idx)})
+		}(i)
+	}
+
+	wg.Wait()
+	assert.Greater(t, receivedCount.Load(), int64(0))
+}

backend/core/extpoints/extpoints_test.go

@@ -0,0 +1,280 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package extpoints_test
+
+import (
+	"context"
+	"testing"
+	"testing/fstest"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/Rain-kl/Wavelet/backend/core"
+	"github.com/Rain-kl/Wavelet/backend/core/extpoints"
+)
+
+func TestRouterExtension(t *testing.T) {
+	r := extpoints.NewRouterRegistry()
+	require.NotNil(t, r)
+
+	mGlobal := "global_middleware"
+	r.Use(mGlobal)
+	assert.Equal(t, []any{mGlobal}, r.Middlewares())
+
+	// Test root methods
+	hRoot := "root_handler"
+	r.GET("/", hRoot)
+	r.POST("/root_post", hRoot)
+	r.PUT("/root_put", hRoot)
+	r.DELETE("/root_del", hRoot)
+	r.PATCH("/root_patch", hRoot)
+	r.HEAD("/root_head", hRoot)
+	r.OPTIONS("/root_opt", hRoot)
+	anyRootDefs := r.Any("/root_any", hRoot)
+	assert.Len(t, anyRootDefs, 7)
+
+	// Group and Group.Use
+	mAPI := "api_middleware"
+	api := r.Group("/api/v1", mAPI)
+	api.Use("api_extra_middleware")
+	assert.Len(t, api.Middlewares(), 2)
+
+	hList := "list_orders_handler"
+	hCreate := "create_order_handler"
+	api.GET("/orders", hList)
+	api.POST("/orders", hCreate)
+
+	mAdmin := "admin_middleware"
+	admin := api.Group("admin", mAdmin)
+
+	hUserGet := "get_user_handler"
+	hUserPut := "put_user_handler"
+	hUserDel := "del_user_handler"
+	hUserPatch := "patch_user_handler"
+	hUserHead := "head_user_handler"
+	hUserOptions := "options_user_handler"
+	admin.GET("/users/:id", hUserGet)
+	admin.PUT("/users/:id", hUserPut)
+	admin.DELETE("/users/:id", hUserDel)
+	admin.PATCH("/users/:id", hUserPatch)
+	admin.HEAD("/users/:id", hUserHead)
+	admin.OPTIONS("/users/:id", hUserOptions)
+
+	hCustom := "custom_handler"
+	admin.Handle("CUSTOM", "/custom", hCustom)
+
+	hAny := "any_handler"
+	anyRoutes := admin.Any("/all", hAny)
+	assert.NotEmpty(t, anyRoutes)
+
+	// Group.Routes() returns root routes
+	assert.Equal(t, r.Routes(), admin.Routes())
+
+	routes := r.Routes()
+
+	// Verify route paths and middlewares
+	var foundOrderGet bool
+	var foundUserPut bool
+	for _, route := range routes {
+		if route.Method == "GET" && route.Path == "/api/v1/orders" {
+			foundOrderGet = true
+			assert.Equal(t, []any{mGlobal, mAPI, "api_extra_middleware"}, route.Middlewares)
+			assert.Equal(t, []any{hList}, route.Handlers)
+		}
+		if route.Method == "PUT" && route.Path == "/api/v1/admin/users/:id" {
+			foundUserPut = true
+			assert.Equal(t, []any{mGlobal, mAPI, "api_extra_middleware", mAdmin}, route.Middlewares)
+			assert.Equal(t, []any{hUserPut}, route.Handlers)
+		}
+	}
+	assert.True(t, foundOrderGet)
+	assert.True(t, foundUserPut)
+}
+
+func TestMigrationExtension(t *testing.T) {
+	m := extpoints.NewMigrationRegistry()
+	require.NotNil(t, m)
+
+	fs1 := fstest.MapFS{
+		"migrations/001_init.sql": &fstest.MapFile{Data: []byte("CREATE TABLE t1(id int);")},
+	}
+	fs2 := fstest.MapFS{
+		"custom/001_order.sql": &fstest.MapFile{Data: []byte("CREATE TABLE t2(id int);")},
+	}
+
+	m.Register("auth", fs1)
+	m.Register("order", fs2, "custom")
+
+	// Update existing entry
+	fs1Updated := fstest.MapFS{
+		"migrations/002_update.sql": &fstest.MapFile{Data: []byte("ALTER TABLE t1 ADD col int;")},
+	}
+	m.Register("auth", fs1Updated, "")
+
+	entries := m.Entries()
+	require.Len(t, entries, 2)
+	assert.Equal(t, "auth", entries[0].PluginID)
+	assert.Equal(t, "migrations", entries[0].Dir)
+	assert.Equal(t, "order", entries[1].PluginID)
+	assert.Equal(t, "custom", entries[1].Dir)
+
+	authEntry, ok := m.Get("auth")
+	assert.True(t, ok)
+	assert.Equal(t, "auth", authEntry.PluginID)
+
+	_, ok = m.Get("non_existent")
+	assert.False(t, ok)
+}
+
+func TestTaskExtension(t *testing.T) {
+	tr := extpoints.NewTaskRegistry()
+	require.NotNil(t, tr)
+
+	handler := func(ctx context.Context, payload []byte) error { return nil }
+
+	tr.Register("order:cancel_timeout", handler,
+		extpoints.WithTaskConcurrency(5),
+		extpoints.WithTaskRetry(3),
+		extpoints.WithTaskTimeout(10*time.Second),
+		extpoints.WithTaskMetadata("queue", "critical"),
+		nil, // test nil option
+	)
+
+	// Re-register to test update
+	tr.Register("order:cancel_timeout", handler,
+		extpoints.WithTaskConcurrency(10),
+		extpoints.WithTaskMetadata("queue", "high"),
+	)
+
+	tasks := tr.Tasks()
+	require.Len(t, tasks, 1)
+	assert.Equal(t, "order:cancel_timeout", tasks[0].Pattern)
+	assert.Equal(t, 10, tasks[0].Concurrency)
+	assert.Equal(t, "high", tasks[0].Metadata["queue"])
+
+	task, ok := tr.Get("order:cancel_timeout")
+	assert.True(t, ok)
+	assert.Equal(t, "order:cancel_timeout", task.Pattern)
+
+	_, ok = tr.Get("unknown")
+	assert.False(t, ok)
+}
+
+func TestScheduleExtension(t *testing.T) {
+	sr := extpoints.NewScheduleRegistry()
+	require.NotNil(t, sr)
+
+	type ReportPayload struct {
+		Type string `json:"type"`
+	}
+
+	sr.RegisterCron("0 2 * * *", "report:daily_summary", ReportPayload{Type: "daily"})
+	sr.Register("@every 1h", "cleanup:expired_sessions", nil,
+		extpoints.WithScheduleOption("retry", 2),
+		nil, // test nil option
+	)
+
+	// Re-register to test update
+	sr.RegisterCron("0 3 * * *", "report:daily_summary", ReportPayload{Type: "all"})
+
+	schedules := sr.Schedules()
+	require.Len(t, schedules, 2)
+
+	assert.Equal(t, "0 3 * * *", schedules[0].Spec)
+	assert.Equal(t, "report:daily_summary", schedules[0].TaskType)
+	assert.Equal(t, ReportPayload{Type: "all"}, schedules[0].Payload)
+
+	assert.Equal(t, "@every 1h", schedules[1].Spec)
+	assert.Equal(t, "cleanup:expired_sessions", schedules[1].TaskType)
+	assert.Equal(t, 2, schedules[1].Options["retry"])
+
+	sched, ok := sr.Get("report:daily_summary")
+	assert.True(t, ok)
+	assert.Equal(t, "0 3 * * *", sched.Spec)
+
+	_, ok = sr.Get("unknown")
+	assert.False(t, ok)
+}
+
+func TestSettingExtension(t *testing.T) {
+	sr := extpoints.NewSettingRegistry()
+	require.NotNil(t, sr)
+
+	assert.Panics(t, func() {
+		sr.Register(extpoints.SettingSchema{}) // empty key panics
+	})
+
+	sr.Register(extpoints.SettingSchema{
+		Key:         "order.auto_cancel_mins",
+		Default:     15,
+		Description: "Order auto cancellation timeout in minutes",
+		Category:    "order",
+		Public:      true,
+	})
+
+	// Re-register to test update
+	sr.Register(extpoints.SettingSchema{
+		Key:         "order.auto_cancel_mins",
+		Default:     30,
+		Description: "Updated timeout",
+	})
+
+	sr.Register(extpoints.SettingSchema{
+		Key:         "auth.jwt_secret",
+		Default:     "default-secret",
+		Description: "JWT secret key",
+		Category:    "auth",
+		ReadOnly:    true,
+	})
+
+	schemas := sr.Schemas()
+	require.Len(t, schemas, 2)
+
+	schema, ok := sr.Get("order.auto_cancel_mins")
+	assert.True(t, ok)
+	assert.Equal(t, 30, schema.Default)
+
+	_, ok = sr.Get("unknown")
+	assert.False(t, ok)
+}
+
+func TestContextExtensionPointsIntegration(t *testing.T) {
+	ctx := core.NewContext(context.Background())
+
+	require.NotNil(t, ctx.Events())
+	require.NotNil(t, ctx.Router())
+	require.NotNil(t, ctx.Migrations())
+	require.NotNil(t, ctx.Tasks())
+	require.NotNil(t, ctx.Task())
+	require.NotNil(t, ctx.Schedules())
+	require.NotNil(t, ctx.Schedule())
+	require.NotNil(t, ctx.Settings())
+	require.NotNil(t, ctx.Setting())
+
+	// Register from child context and verify shared application registry
+	child := ctx.Fork()
+	child.Router().GET("/ping", "pong_handler")
+	child.Task().Register("sample:task", "handler")
+	child.Schedule().RegisterCron("@hourly", "sample:cron", nil)
+	child.Settings().Register(extpoints.SettingSchema{
+		Key:     "app.name",
+		Default: "Wavelet",
+	})
+
+	assert.Len(t, ctx.Router().Routes(), 1)
+	assert.Len(t, ctx.Tasks().Tasks(), 1)
+	assert.Len(t, ctx.Schedules().Schedules(), 1)
+	assert.Len(t, ctx.Settings().Schemas(), 1)
+
+	// Child and root events
+	var eventReceived bool
+	child.Events().On("app:ready", func() {
+		eventReceived = true
+	})
+	err := ctx.Events().Emit(context.Background(), "app:ready", nil)
+	assert.NoError(t, err)
+	assert.True(t, eventReceived)
+}

backend/core/extpoints/migration.go

@@ -0,0 +1,87 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+// Package extpoints defines extension points for router, migrations, tasks, schedules, and settings.
+package extpoints
+
+import (
+	"io/fs"
+	"sync"
+)
+
+// MigrationEntry contains the migration filesystem and configuration for a plugin.
+type MigrationEntry struct {
+	PluginID string
+	FS       fs.FS
+	Dir      string
+}
+
+// MigrationExtension defines the interface for registering and querying plugin migrations.
+type MigrationExtension interface {
+	Register(pluginID string, fsys fs.FS, dir ...string)
+	Entries() []MigrationEntry
+	Get(pluginID string) (MigrationEntry, bool)
+}
+
+// MigrationRegistry collects and stores migration entries from plugins.
+type MigrationRegistry struct {
+	mu      sync.RWMutex
+	entries []MigrationEntry
+	lookup  map[string]MigrationEntry
+}
+
+// NewMigrationRegistry creates a new migration registry.
+func NewMigrationRegistry() *MigrationRegistry {
+	return &MigrationRegistry{
+		lookup: make(map[string]MigrationEntry),
+	}
+}
+
+// Register adds a migration entry for a plugin.
+// If dir is not specified, it defaults to "migrations".
+func (m *MigrationRegistry) Register(pluginID string, fsys fs.FS, dir ...string) {
+	m.mu.Lock()
+	defer m.mu.Unlock()
+
+	migrationDir := "migrations"
+	if len(dir) > 0 && dir[0] != "" {
+		migrationDir = dir[0]
+	}
+
+	entry := MigrationEntry{
+		PluginID: pluginID,
+		FS:       fsys,
+		Dir:      migrationDir,
+	}
+
+	// If entry already exists, update in-place; otherwise append
+	if _, exists := m.lookup[pluginID]; exists {
+		for i, e := range m.entries {
+			if e.PluginID == pluginID {
+				m.entries[i] = entry
+				break
+			}
+		}
+	} else {
+		m.entries = append(m.entries, entry)
+	}
+
+	m.lookup[pluginID] = entry
+}
+
+// Entries returns a copy of all registered migration entries in registration order.
+func (m *MigrationRegistry) Entries() []MigrationEntry {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	res := make([]MigrationEntry, len(m.entries))
+	copy(res, m.entries)
+	return res
+}
+
+// Get retrieves the migration entry for a specific plugin ID.
+func (m *MigrationRegistry) Get(pluginID string) (MigrationEntry, bool) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+	e, ok := m.lookup[pluginID]
+	return e, ok
+}

backend/core/extpoints/router.go

@@ -0,0 +1,269 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package extpoints
+
+import (
+	"strings"
+	"sync"
+)
+
+// RouteDefinition holds the metadata and handler list for a single HTTP route.
+type RouteDefinition struct {
+	Method      string
+	Path        string
+	Handlers    []any
+	Middlewares []any
+}
+
+// RouterExtension defines the interface for registering routes and middlewares.
+type RouterExtension interface {
+	Use(middlewares ...any)
+	Group(prefix string, middlewares ...any) RouterExtension
+	Handle(method string, path string, handlers ...any) RouteDefinition
+	GET(path string, handlers ...any) RouteDefinition
+	POST(path string, handlers ...any) RouteDefinition
+	PUT(path string, handlers ...any) RouteDefinition
+	DELETE(path string, handlers ...any) RouteDefinition
+	PATCH(path string, handlers ...any) RouteDefinition
+	HEAD(path string, handlers ...any) RouteDefinition
+	OPTIONS(path string, handlers ...any) RouteDefinition
+	Any(path string, handlers ...any) []RouteDefinition
+	Routes() []RouteDefinition
+	Middlewares() []any
+}
+
+// RouterRegistry implements RouterExtension as the root route and middleware collector.
+type RouterRegistry struct {
+	mu          sync.RWMutex
+	routes      []RouteDefinition
+	middlewares []any
+}
+
+// NewRouterRegistry creates a new root router collector.
+func NewRouterRegistry() *RouterRegistry {
+	return &RouterRegistry{}
+}
+
+// Use registers global middlewares to the router.
+func (r *RouterRegistry) Use(middlewares ...any) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	r.middlewares = append(r.middlewares, middlewares...)
+}
+
+// Middlewares returns a copy of registered root middlewares.
+func (r *RouterRegistry) Middlewares() []any {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	res := make([]any, len(r.middlewares))
+	copy(res, r.middlewares)
+	return res
+}
+
+// Group creates a new RouteGroup under the router.
+func (r *RouterRegistry) Group(prefix string, middlewares ...any) RouterExtension {
+	return &RouterGroup{
+		registry:    r,
+		prefix:      cleanPath(prefix),
+		middlewares: middlewares,
+	}
+}
+
+// Handle registers a route with a custom HTTP method and handlers.
+func (r *RouterRegistry) Handle(method, path string, handlers ...any) RouteDefinition {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	rd := RouteDefinition{
+		Method:      strings.ToUpper(method),
+		Path:        cleanPath(path),
+		Handlers:    handlers,
+		Middlewares: append([]any(nil), r.middlewares...),
+	}
+	r.routes = append(r.routes, rd)
+	return rd
+}
+
+// GET registers a GET route.
+func (r *RouterRegistry) GET(path string, handlers ...any) RouteDefinition {
+	return r.Handle("GET", path, handlers...)
+}
+
+// POST registers a POST route.
+func (r *RouterRegistry) POST(path string, handlers ...any) RouteDefinition {
+	return r.Handle("POST", path, handlers...)
+}
+
+// PUT registers a PUT route.
+func (r *RouterRegistry) PUT(path string, handlers ...any) RouteDefinition {
+	return r.Handle("PUT", path, handlers...)
+}
+
+// DELETE registers a DELETE route.
+func (r *RouterRegistry) DELETE(path string, handlers ...any) RouteDefinition {
+	return r.Handle("DELETE", path, handlers...)
+}
+
+// PATCH registers a PATCH route.
+func (r *RouterRegistry) PATCH(path string, handlers ...any) RouteDefinition {
+	return r.Handle("PATCH", path, handlers...)
+}
+
+// HEAD registers a HEAD route.
+func (r *RouterRegistry) HEAD(path string, handlers ...any) RouteDefinition {
+	return r.Handle("HEAD", path, handlers...)
+}
+
+// OPTIONS registers an OPTIONS route.
+func (r *RouterRegistry) OPTIONS(path string, handlers ...any) RouteDefinition {
+	return r.Handle("OPTIONS", path, handlers...)
+}
+
+// Any registers a route for standard HTTP methods.
+func (r *RouterRegistry) Any(path string, handlers ...any) []RouteDefinition {
+	methods := []string{"GET", "POST", "PUT", "DELETE", "PATCH", "HEAD", "OPTIONS"}
+	defs := make([]RouteDefinition, 0, len(methods))
+	for _, m := range methods {
+		defs = append(defs, r.Handle(m, path, handlers...))
+	}
+	return defs
+}
+
+// Routes returns a copy of all collected RouteDefinitions.
+func (r *RouterRegistry) Routes() []RouteDefinition {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+	res := make([]RouteDefinition, len(r.routes))
+	copy(res, r.routes)
+	return res
+}
+
+// RouterGroup represents a scoped route group with a path prefix and group-level middlewares.
+type RouterGroup struct {
+	registry    *RouterRegistry
+	prefix      string
+	middlewares []any
+}
+
+// Use adds middlewares to this group.
+func (g *RouterGroup) Use(middlewares ...any) {
+	g.middlewares = append(g.middlewares, middlewares...)
+}
+
+// Group creates a nested RouteGroup.
+func (g *RouterGroup) Group(prefix string, middlewares ...any) RouterExtension {
+	combinedPrefix := joinPaths(g.prefix, prefix)
+	combinedMiddlewares := make([]any, 0, len(g.middlewares)+len(middlewares))
+	combinedMiddlewares = append(combinedMiddlewares, g.middlewares...)
+	combinedMiddlewares = append(combinedMiddlewares, middlewares...)
+
+	return &RouterGroup{
+		registry:    g.registry,
+		prefix:      combinedPrefix,
+		middlewares: combinedMiddlewares,
+	}
+}
+
+// Handle registers a route under this group.
+func (g *RouterGroup) Handle(method, path string, handlers ...any) RouteDefinition {
+	g.registry.mu.Lock()
+	defer g.registry.mu.Unlock()
+
+	fullPath := joinPaths(g.prefix, path)
+
+	allMiddlewares := make([]any, 0, len(g.registry.middlewares)+len(g.middlewares))
+	allMiddlewares = append(allMiddlewares, g.registry.middlewares...)
+	allMiddlewares = append(allMiddlewares, g.middlewares...)
+
+	rd := RouteDefinition{
+		Method:      strings.ToUpper(method),
+		Path:        fullPath,
+		Handlers:    handlers,
+		Middlewares: allMiddlewares,
+	}
+	g.registry.routes = append(g.registry.routes, rd)
+	return rd
+}
+
+// GET registers a GET route in this group.
+func (g *RouterGroup) GET(path string, handlers ...any) RouteDefinition {
+	return g.Handle("GET", path, handlers...)
+}
+
+// POST registers a POST route in this group.
+func (g *RouterGroup) POST(path string, handlers ...any) RouteDefinition {
+	return g.Handle("POST", path, handlers...)
+}
+
+// PUT registers a PUT route in this group.
+func (g *RouterGroup) PUT(path string, handlers ...any) RouteDefinition {
+	return g.Handle("PUT", path, handlers...)
+}
+
+// DELETE registers a DELETE route in this group.
+func (g *RouterGroup) DELETE(path string, handlers ...any) RouteDefinition {
+	return g.Handle("DELETE", path, handlers...)
+}
+
+// PATCH registers a PATCH route in this group.
+func (g *RouterGroup) PATCH(path string, handlers ...any) RouteDefinition {
+	return g.Handle("PATCH", path, handlers...)
+}
+
+// HEAD registers a HEAD route in this group.
+func (g *RouterGroup) HEAD(path string, handlers ...any) RouteDefinition {
+	return g.Handle("HEAD", path, handlers...)
+}
+
+// OPTIONS registers an OPTIONS route in this group.
+func (g *RouterGroup) OPTIONS(path string, handlers ...any) RouteDefinition {
+	return g.Handle("OPTIONS", path, handlers...)
+}
+
+// Any registers a route in this group for standard HTTP methods.
+func (g *RouterGroup) Any(path string, handlers ...any) []RouteDefinition {
+	methods := []string{"GET", "POST", "PUT", "DELETE", "PATCH", "HEAD", "OPTIONS"}
+	defs := make([]RouteDefinition, 0, len(methods))
+	for _, m := range methods {
+		defs = append(defs, g.Handle(m, path, handlers...))
+	}
+	return defs
+}
+
+// Routes returns all routes from the parent registry.
+func (g *RouterGroup) Routes() []RouteDefinition {
+	return g.registry.Routes()
+}
+
+// Middlewares returns a copy of the group's middlewares.
+func (g *RouterGroup) Middlewares() []any {
+	res := make([]any, len(g.middlewares))
+	copy(res, g.middlewares)
+	return res
+}
+
+func cleanPath(p string) string {
+	if p == "" {
+		return "/"
+	}
+	if !strings.HasPrefix(p, "/") {
+		p = "/" + p
+	}
+	if len(p) > 1 && strings.HasSuffix(p, "/") {
+		p = strings.TrimSuffix(p, "/")
+	}
+	return p
+}
+
+func joinPaths(base, relative string) string {
+	if base == "" || base == "/" {
+		return cleanPath(relative)
+	}
+	if relative == "" || relative == "/" {
+		return cleanPath(base)
+	}
+	base = strings.TrimSuffix(base, "/")
+	relative = strings.TrimPrefix(relative, "/")
+	return cleanPath(base + "/" + relative)
+}

backend/core/extpoints/schedule.go

@@ -0,0 +1,103 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package extpoints
+
+import "sync"
+
+// ScheduleDefinition holds the configuration for a scheduled/cron task.
+type ScheduleDefinition struct {
+	Spec     string
+	TaskType string
+	Payload  any
+	Options  map[string]any
+}
+
+// ScheduleOption configures a ScheduleDefinition.
+type ScheduleOption func(*ScheduleDefinition)
+
+// WithScheduleOption adds a custom option to the schedule definition.
+func WithScheduleOption(key string, val any) ScheduleOption {
+	return func(sd *ScheduleDefinition) {
+		if sd.Options == nil {
+			sd.Options = make(map[string]any)
+		}
+		sd.Options[key] = val
+	}
+}
+
+// ScheduleExtension defines the interface for registering and querying cron/scheduled tasks.
+type ScheduleExtension interface {
+	Register(spec string, taskType string, payload any, opts ...ScheduleOption)
+	RegisterCron(spec string, taskType string, payload any, opts ...ScheduleOption)
+	Schedules() []ScheduleDefinition
+	Get(taskType string) (ScheduleDefinition, bool)
+}
+
+// ScheduleRegistry collects and manages schedule registrations.
+type ScheduleRegistry struct {
+	mu        sync.RWMutex
+	schedules []ScheduleDefinition
+	lookup    map[string]ScheduleDefinition
+}
+
+// NewScheduleRegistry creates a new schedule registry.
+func NewScheduleRegistry() *ScheduleRegistry {
+	return &ScheduleRegistry{
+		lookup: make(map[string]ScheduleDefinition),
+	}
+}
+
+// Register adds a schedule definition.
+func (s *ScheduleRegistry) Register(spec string, taskType string, payload any, opts ...ScheduleOption) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	sd := ScheduleDefinition{
+		Spec:     spec,
+		TaskType: taskType,
+		Payload:  payload,
+		Options:  make(map[string]any),
+	}
+
+	for _, opt := range opts {
+		if opt != nil {
+			opt(&sd)
+		}
+	}
+
+	if _, exists := s.lookup[taskType]; exists {
+		for i, item := range s.schedules {
+			if item.TaskType == taskType {
+				s.schedules[i] = sd
+				break
+			}
+		}
+	} else {
+		s.schedules = append(s.schedules, sd)
+	}
+
+	s.lookup[taskType] = sd
+}
+
+// RegisterCron is an alias for Register.
+func (s *ScheduleRegistry) RegisterCron(spec string, taskType string, payload any, opts ...ScheduleOption) {
+	s.Register(spec, taskType, payload, opts...)
+}
+
+// Schedules returns a copy of all registered ScheduleDefinitions.
+func (s *ScheduleRegistry) Schedules() []ScheduleDefinition {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	res := make([]ScheduleDefinition, len(s.schedules))
+	copy(res, s.schedules)
+	return res
+}
+
+// Get retrieves a schedule definition by its task type.
+func (s *ScheduleRegistry) Get(taskType string) (ScheduleDefinition, bool) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	sd, ok := s.lookup[taskType]
+	return sd, ok
+}

backend/core/extpoints/setting.go

@@ -0,0 +1,80 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package extpoints
+
+import "sync"
+
+// SettingSchema defines the configuration schema and metadata for a system or plugin setting.
+type SettingSchema struct {
+	Key         string `json:"key"`
+	Default     any    `json:"default"`
+	Description string `json:"description"`
+	Type        string `json:"type,omitempty"`
+	ReadOnly    bool   `json:"read_only,omitempty"`
+	Public      bool   `json:"public,omitempty"`
+	Category    string `json:"category,omitempty"`
+	Validation  string `json:"validation,omitempty"`
+}
+
+// SettingExtension defines the interface for registering and querying setting configuration schemas.
+type SettingExtension interface {
+	Register(schema SettingSchema)
+	Schemas() []SettingSchema
+	Get(key string) (SettingSchema, bool)
+}
+
+// SettingRegistry collects and manages setting configuration schemas.
+type SettingRegistry struct {
+	mu      sync.RWMutex
+	schemas []SettingSchema
+	lookup  map[string]SettingSchema
+}
+
+// NewSettingRegistry creates a new setting schema registry.
+func NewSettingRegistry() *SettingRegistry {
+	return &SettingRegistry{
+		lookup: make(map[string]SettingSchema),
+	}
+}
+
+// Register registers a SettingSchema into the registry.
+// Panics if the schema Key is empty.
+func (s *SettingRegistry) Register(schema SettingSchema) {
+	if schema.Key == "" {
+		panic("core/extpoints: setting schema key cannot be empty")
+	}
+
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	if _, exists := s.lookup[schema.Key]; exists {
+		for i, item := range s.schemas {
+			if item.Key == schema.Key {
+				s.schemas[i] = schema
+				break
+			}
+		}
+	} else {
+		s.schemas = append(s.schemas, schema)
+	}
+
+	s.lookup[schema.Key] = schema
+}
+
+// Schemas returns a copy of all registered SettingSchemas.
+func (s *SettingRegistry) Schemas() []SettingSchema {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	res := make([]SettingSchema, len(s.schemas))
+	copy(res, s.schemas)
+	return res
+}
+
+// Get retrieves a SettingSchema by its key.
+func (s *SettingRegistry) Get(key string) (SettingSchema, bool) {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	schema, ok := s.lookup[key]
+	return schema, ok
+}

backend/core/extpoints/task.go

@@ -0,0 +1,122 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package extpoints
+
+import (
+	"sync"
+	"time"
+)
+
+// TaskDefinition holds the definition and runtime options for an asynchronous background task.
+type TaskDefinition struct {
+	Pattern     string
+	Handler     any
+	Concurrency int
+	Retry       int
+	Timeout     time.Duration
+	Metadata    map[string]any
+}
+
+// TaskOption configures a TaskDefinition.
+type TaskOption func(*TaskDefinition)
+
+// WithTaskConcurrency sets the concurrency limit for the task.
+func WithTaskConcurrency(concurrency int) TaskOption {
+	return func(td *TaskDefinition) {
+		td.Concurrency = concurrency
+	}
+}
+
+// WithTaskRetry sets the maximum retry count for the task.
+func WithTaskRetry(retry int) TaskOption {
+	return func(td *TaskDefinition) {
+		td.Retry = retry
+	}
+}
+
+// WithTaskTimeout sets the execution timeout for the task.
+func WithTaskTimeout(timeout time.Duration) TaskOption {
+	return func(td *TaskDefinition) {
+		td.Timeout = timeout
+	}
+}
+
+// WithTaskMetadata adds a key-value pair to the task metadata.
+func WithTaskMetadata(key string, val any) TaskOption {
+	return func(td *TaskDefinition) {
+		if td.Metadata == nil {
+			td.Metadata = make(map[string]any)
+		}
+		td.Metadata[key] = val
+	}
+}
+
+// TaskExtension defines the interface for registering and querying background task handlers.
+type TaskExtension interface {
+	Register(pattern string, handler any, opts ...TaskOption)
+	Tasks() []TaskDefinition
+	Get(pattern string) (TaskDefinition, bool)
+}
+
+// TaskRegistry collects and manages task registrations.
+type TaskRegistry struct {
+	mu     sync.RWMutex
+	tasks  []TaskDefinition
+	lookup map[string]TaskDefinition
+}
+
+// NewTaskRegistry creates a new task registry.
+func NewTaskRegistry() *TaskRegistry {
+	return &TaskRegistry{
+		lookup: make(map[string]TaskDefinition),
+	}
+}
+
+// Register registers a task pattern and its handler with optional configuration.
+func (t *TaskRegistry) Register(pattern string, handler any, opts ...TaskOption) {
+	t.mu.Lock()
+	defer t.mu.Unlock()
+
+	td := TaskDefinition{
+		Pattern:  pattern,
+		Handler:  handler,
+		Metadata: make(map[string]any),
+	}
+
+	for _, opt := range opts {
+		if opt != nil {
+			opt(&td)
+		}
+	}
+
+	if _, exists := t.lookup[pattern]; exists {
+		for i, item := range t.tasks {
+			if item.Pattern == pattern {
+				t.tasks[i] = td
+				break
+			}
+		}
+	} else {
+		t.tasks = append(t.tasks, td)
+	}
+
+	t.lookup[pattern] = td
+}
+
+// Tasks returns a copy of all registered TaskDefinitions.
+func (t *TaskRegistry) Tasks() []TaskDefinition {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	res := make([]TaskDefinition, len(t.tasks))
+	copy(res, t.tasks)
+	return res
+}
+
+// Get retrieves a task definition by its pattern.
+func (t *TaskRegistry) Get(pattern string) (TaskDefinition, bool) {
+	t.mu.RLock()
+	defer t.mu.RUnlock()
+	td, ok := t.lookup[pattern]
+	return td, ok
+}

backend/core/manifest.go

@@ -0,0 +1,38 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core
+
+import (
+	"fmt"
+	"strings"
+)
+
+// Manifest defines the metadata and dependency declarations for a plugin.
+type Manifest struct {
+	// Name is the unique identifier for the plugin (e.g. "auth", "user", "order").
+	Name string `json:"name" yaml:"name"`
+
+	// Version is the semantic version string of the plugin (e.g. "1.0.0").
+	Version string `json:"version,omitempty" yaml:"version,omitempty"`
+
+	// Description gives a brief summary of the plugin capabilities.
+	Description string `json:"description,omitempty" yaml:"description,omitempty"`
+
+	// Author specifies the author or maintainer of the plugin.
+	Author string `json:"author,omitempty" yaml:"author,omitempty"`
+
+	// Dependencies lists the plugin names that this plugin depends on.
+	Dependencies []string `json:"dependencies,omitempty" yaml:"dependencies,omitempty"`
+
+	// Metadata holds arbitrary plugin-specific metadata.
+	Metadata map[string]any `json:"metadata,omitempty" yaml:"metadata,omitempty"`
+}
+
+// Validate checks whether the manifest satisfies basic integrity requirements.
+func (m Manifest) Validate() error {
+	if strings.TrimSpace(m.Name) == "" {
+		return fmt.Errorf("%w: %w", ErrInvalidManifest, ErrInvalidManifestName)
+	}
+	return nil
+}

backend/core/types.go

@@ -0,0 +1,150 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package core
+
+import (
+	"context"
+	"errors"
+
+	"github.com/Rain-kl/Wavelet/backend/core/extpoints"
+)
+
+// Standard sentinel errors returned by core operations.
+var (
+	// ErrServiceNotFound is returned when a requested service is not registered in the IoC container.
+	ErrServiceNotFound = errors.New("core: service not found")
+
+	// ErrServiceNotReady is returned when one or more required services are not ready in Using/UsingN.
+	ErrServiceNotReady = errors.New("core: service not ready")
+
+	// ErrNilContext is returned when a nil Context is passed to an operation requiring a valid Context.
+	ErrNilContext = errors.New("core: context is nil")
+
+	// ErrNilService is returned when attempting to provide a nil service implementation.
+	ErrNilService = errors.New("core: service is nil")
+
+	// ErrInvalidManifest is returned when a plugin manifest fails validation.
+	ErrInvalidManifest = errors.New("core: invalid manifest")
+
+	// ErrInvalidManifestName is returned when a plugin manifest has an empty name.
+	ErrInvalidManifestName = errors.New("core: manifest name is required")
+
+	// ErrDriverNotFound is returned when a requested driver type is not registered.
+	ErrDriverNotFound = errors.New("core: driver not found")
+
+	// ErrAppRunning is returned when attempting to start an already running App.
+	ErrAppRunning = errors.New("core: app is already running")
+
+	// ErrAppNotRunning is returned when attempting to operate on an App that is not running.
+	ErrAppNotRunning = errors.New("core: app is not running")
+)
+
+// Plugin is the unified contract for all core and downstream plugins.
+type Plugin interface {
+	// Name returns the globally unique identifier of the plugin (e.g. "auth", "database").
+	Name() string
+	// Apply is the core mounting entrypoint: provides services, registers routes, tasks, and event listeners.
+	Apply(ctx *Context) error
+}
+
+// PluginWithManifest is an optional extension interface for plugins that declare metadata.
+type PluginWithManifest interface {
+	Plugin
+	Manifest() Manifest
+}
+
+// DriverType identifies the category of a runtime driver engine.
+type DriverType string
+
+const (
+	// DriverTypeHTTP represents HTTP web server drivers (e.g. Gin).
+	DriverTypeHTTP DriverType = "http"
+
+	// DriverTypeWorker represents asynchronous background worker drivers (e.g. Asynq worker server).
+	DriverTypeWorker DriverType = "worker"
+
+	// DriverTypeScheduler represents cron and timer schedule drivers (e.g. Asynq scheduler).
+	DriverTypeScheduler DriverType = "schedule"
+)
+
+// Driver is a runtime engine that manages an event loop or listening port.
+type Driver interface {
+	// Type returns the category of this driver engine.
+	Type() DriverType
+	// Start starts the driver lifecycle loop.
+	Start(ctx context.Context) error
+	// Stop gracefully shuts down the driver.
+	Stop(ctx context.Context) error
+}
+
+// Profile identifies the runtime aspect or execution mode of an application.
+type Profile string
+
+const (
+	// ProfileAPI runs HTTP API server drivers.
+	ProfileAPI Profile = "api"
+
+	// ProfileWorker runs asynchronous background worker drivers.
+	ProfileWorker Profile = "worker"
+
+	// ProfileSchedule runs cron and timer schedule drivers.
+	ProfileSchedule Profile = "schedule"
+
+	// ProfileAll runs all registered drivers concurrently in fused mode.
+	ProfileAll Profile = "all"
+)
+
+// MigrationEngine is the interface for executing database migrations across registered plugins.
+// The ctx parameter is the root micro-kernel Context, allowing the engine to resolve
+// services from the IoC container via core.Inject or core.Using.
+type MigrationEngine interface {
+	Migrate(ctx *Context, entries []MigrationEntry) error
+}
+
+// MigrationRunner is a function adapter implementing MigrationEngine.
+type MigrationRunner func(ctx *Context, entries []MigrationEntry) error
+
+// Migrate calls the underlying migration function.
+func (fn MigrationRunner) Migrate(ctx *Context, entries []MigrationEntry) error {
+	return fn(ctx, entries)
+}
+
+// Disposer is a cleanup function executed when a Context is disposed.
+type Disposer func() error
+
+// RouterExtension re-exports extpoints.RouterExtension.
+type RouterExtension = extpoints.RouterExtension
+
+// RouteDefinition re-exports extpoints.RouteDefinition.
+type RouteDefinition = extpoints.RouteDefinition
+
+// MigrationExtension re-exports extpoints.MigrationExtension.
+type MigrationExtension = extpoints.MigrationExtension
+
+// MigrationEntry re-exports extpoints.MigrationEntry.
+type MigrationEntry = extpoints.MigrationEntry
+
+// TaskExtension re-exports extpoints.TaskExtension.
+type TaskExtension = extpoints.TaskExtension
+
+// TaskDefinition re-exports extpoints.TaskDefinition.
+type TaskDefinition = extpoints.TaskDefinition
+
+// TaskOption re-exports extpoints.TaskOption.
+type TaskOption = extpoints.TaskOption
+
+// ScheduleExtension re-exports extpoints.ScheduleExtension.
+type ScheduleExtension = extpoints.ScheduleExtension
+
+// ScheduleDefinition re-exports extpoints.ScheduleDefinition.
+type ScheduleDefinition = extpoints.ScheduleDefinition
+
+// ScheduleOption re-exports extpoints.ScheduleOption.
+type ScheduleOption = extpoints.ScheduleOption
+
+// SettingExtension re-exports extpoints.SettingExtension.
+type SettingExtension = extpoints.SettingExtension
+
+// SettingSchema re-exports extpoints.SettingSchema.
+type SettingSchema = extpoints.SettingSchema