feat(server): implement management endpoints and redis sync

Enable full resource management via API and support data plane
synchronization.

- Add CRUD handlers for Providers, Models, and Keys using DTOs
- Implement LogWriter service for asynchronous, batched audit logging
- Update SyncService to snapshot full configuration state to Redis
- Register new API routes and initialize background services
- Add configuration options for logging performance tuning

cmd/server/main.go

@@ -57,13 +57,22 @@ func main() {
 	log.Println("Connected to PostgreSQL successfully")
 
 	// Auto Migrate
-	if err := db.AutoMigrate(&model.User{}, &model.Provider{}, &model.Key{}, &model.Model{}); err != nil {
+	if err := db.AutoMigrate(&model.User{}, &model.Provider{}, &model.Key{}, &model.Model{}, &model.LogRecord{}); err != nil {
 		log.Fatalf("Failed to auto migrate: %v", err)
 	}
 
 	// 4. Setup Services and Handlers
 	syncService := service.NewSyncService(rdb)
-	handler := api.NewHandler(db, syncService)
+	logWriter := service.NewLogWriter(db, cfg.Log.QueueCapacity, cfg.Log.BatchSize, cfg.Log.FlushInterval)
+	logCtx, cancelLogs := context.WithCancel(context.Background())
+	defer cancelLogs()
+	logWriter.Start(logCtx)
+	handler := api.NewHandler(db, syncService, logWriter)
+
+	// 4.1 Prime Redis snapshots so DP can start with data
+	if err := syncService.SyncAll(db); err != nil {
+		log.Printf("Initial sync warning: %v", err)
+	}
 
 	// 5. Setup Gin Router
 	r := gin.Default()
@@ -74,7 +83,12 @@ func main() {
 	})
 
 	// API Routes
+	r.POST("/providers", handler.CreateProvider)
 	r.POST("/keys", handler.CreateKey)
+	r.POST("/models", handler.CreateModel)
+	r.GET("/models", handler.ListModels)
+	r.POST("/sync/snapshot", handler.SyncSnapshot)
+	r.POST("/logs", handler.IngestLog)
 
 	srv := &http.Server{
 		Addr:    ":" + cfg.Server.Port,