refactor(architecture): eliminate internal package and complete cordis single-owner model and repository migration

- Physically purged all legacy internal/ packages, centralized pkg/model/ and pkg/repository/
- Migrated domain models and database repositories into self-contained owner plugins (user, auth, message_gateway, admin, upload, risk_control)
- Decoupled cross-plugin interactions via pure core/contracts and typed EventBus
- Ensured 100% test coverage pass, zero data races (-race clean), and 0 lint issues in make code-check

pkg/persistence/migrator/migrator_test.go

@@ -0,0 +1,74 @@
+// Copyright 2026 Arctel.net
+// SPDX-License-Identifier: Apache-2.0
+
+package migrator
+
+import (
+	"testing"
+
+	"github.com/Rain-kl/Wavelet/pkg/config"
+	db "github.com/Rain-kl/Wavelet/pkg/persistence"
+	"github.com/alicebob/miniredis/v2"
+	"github.com/glebarez/sqlite"
+	"github.com/redis/go-redis/v9"
+	"github.com/redis/go-redis/v9/maintnotifications"
+	"gorm.io/gorm"
+)
+
+const expectedMigratedSystemConfigCount = 35
+
+func TestMigrateInitializesSQLiteDatabase(t *testing.T) {
+	sqliteDB, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{
+		DisableForeignKeyConstraintWhenMigrating: true,
+	})
+	if err != nil {
+		t.Fatalf("gorm.Open(sqlite) error = %v", err)
+	}
+
+	mr, err := miniredis.Run()
+	if err != nil {
+		t.Fatalf("miniredis.Run() error = %v", err)
+	}
+	redisClient := redis.NewClient(&redis.Options{
+		Addr: mr.Addr(),
+		MaintNotificationsConfig: &maintnotifications.Config{
+			Mode: maintnotifications.ModeDisabled,
+		},
+	})
+
+	previousDBEnabled := config.Config.Database.Enabled
+	config.Config.Database.Enabled = false
+	db.SetDB(sqliteDB)
+	t.Cleanup(func() {
+		config.Config.Database.Enabled = previousDBEnabled
+		db.SetDB(nil)
+		_ = redisClient.Close()
+		mr.Close()
+	})
+
+	Migrate()
+
+	var systemConfigCount int64
+	if err := sqliteDB.Table("w_system_configs").Count(&systemConfigCount).Error; err != nil {
+		t.Fatalf("Migrate() count w_system_configs error = %v", err)
+	}
+	if systemConfigCount != expectedMigratedSystemConfigCount {
+		t.Errorf("Migrate() w_system_configs count = %d, want %d", systemConfigCount, expectedMigratedSystemConfigCount)
+	}
+
+	var adminCount int64
+	if err := sqliteDB.Table("w_users").Where("username = ?", "admin").Count(&adminCount).Error; err != nil {
+		t.Fatalf("Migrate() count admin user error = %v", err)
+	}
+	if adminCount != 1 {
+		t.Errorf("Migrate() admin user count = %d, want %d", adminCount, 1)
+	}
+
+	var templateCount int64
+	if err := sqliteDB.Table("w_templates").Count(&templateCount).Error; err != nil {
+		t.Fatalf("Migrate() count templates error = %v", err)
+	}
+	if templateCount != 2 {
+		t.Errorf("Migrate() templates count = %d, want %d", templateCount, 2)
+	}
+}