refactor(core): align with cordis spatiotemporal composability architecture

- Purify core micro-kernel by removing context hardcoded helpers and reverse dependencies
- Eliminate init() side effects in infra plugins with reversible lifecycle disposal
- Completely isolate plugins by removing cross-plugin imports and using core/contracts
- Introduce TaskService and RiskControlService contracts for unified cross-plugin APIs
- Regenerate Swagger documentation and update developer guide matrix
- Achieve 0 violations in check_cordis_architecture.sh and 100% test pass

backend/plugins/infra/database/plugin.go

@@ -7,9 +7,10 @@ package database
 import (
 	"context"
 
+	"gorm.io/gorm"
+
 	"Wavelet/core"
 	"Wavelet/core/contracts"
-	"gorm.io/gorm"
 )
 
 // Option configures the database plugin.
@@ -60,7 +61,11 @@ func (p *Plugin) Name() string {
 func (p *Plugin) Apply(ctx *core.Context) error {
 	targetDB := p.db
 	if targetDB == nil {
-		targetDB = DB(context.Background())
+		var err error
+		targetDB, err = InitDB()
+		if err != nil {
+			return err
+		}
 	}
 
 	svc := &dbServiceImpl{
@@ -68,10 +73,21 @@ func (p *Plugin) Apply(ctx *core.Context) error {
 		namedDBs: p.namedDBs,
 	}
 
+	if sqlDB, err := targetDB.DB(); err == nil && sqlDB != nil {
+		ctx.OnDispose(func() error {
+			return sqlDB.Close()
+		})
+	}
+
 	core.Provide[contracts.DBService](ctx, svc)
 	return nil
 }
 
+// NewService wraps a GORM DB instance into a contracts.DBService.
+func NewService(primary *gorm.DB) contracts.DBService {
+	return &dbServiceImpl{primary: primary}
+}
+
 type dbServiceImpl struct {
 	primary  *gorm.DB
 	namedDBs map[string]*gorm.DB