Go: add migrate database flag (#16719)

### Summary

--migrate will trigger database migration
```
./ragflow_main --api --migrate
```

Signed-off-by: Jin Hai <haijin.chn@gmail.com>

cmd/ragflow_server.go

@@ -62,6 +62,7 @@ type serverArgs struct {
 	helpFlag      bool
 	versionFlag   bool
 	debugLog      bool
+	migrateDB     bool
 	configPath    *string // Used by admin, api; user defined config path
 	initSuperUser bool    // Used by admin;
 	port          *int    // Used by admin, api
@@ -81,6 +82,8 @@ func parseArgs() (*serverArgs, error) {
 		case "--admin":
 			serverMode = "admin"
 			args.mode = &serverMode
+		case "--migrate":
+			args.migrateDB = true
 		case "--ingestor":
 			serverMode = "ingestor"
 			args.mode = &serverMode
@@ -335,7 +338,7 @@ func main() {
 	server.PrintAll()
 
 	// Initialize database
-	if err = dao.InitDB(); err != nil {
+	if err = dao.InitDB(arguments.migrateDB); err != nil {
 		common.Fatal("Failed to initialize database", zap.Error(err))
 	}
 

internal/dao/database.go

@@ -65,7 +65,7 @@ type LLMFactoriesFile struct {
 }
 
 // InitDB initialize database connection
-func InitDB() error {
+func InitDB(migrateDB bool) error {
 	cfg := server.GetConfig()
 	dbCfg := cfg.Database
 
@@ -160,17 +160,20 @@ func InitDB() error {
 		&entity.FileCommitItem{},
 	}
 
-	for _, m := range dataModels {
-		if err = autoMigrateSafely(DB, m); err != nil {
-			return fmt.Errorf("failed to migrate model %T: %w", m, err)
+	if migrateDB {
+		common.Info("Migrating database schema...")
+		for _, m := range dataModels {
+			if err = autoMigrateSafely(DB, m); err != nil {
+				return fmt.Errorf("failed to migrate model %T: %w", m, err)
+			}
 		}
-	}
 
-	// Run manual migrations for complex schema changes
-	if err = RunMigrations(DB); err != nil {
-		return fmt.Errorf("failed to run manual migrations: %w", err)
+		// Run manual migrations for complex schema changes
+		if err = RunMigrations(DB); err != nil {
+			return fmt.Errorf("failed to run manual migrations: %w", err)
+		}
+		common.Info("Database schema migrated successfully")
 	}
-
 	// Seed built-in agent templates so the Go backend can serve the
 	// "create agent from template" catalogue without relying on Python-side
 	// initialization.