Replace Gorush with direct APNs/FCM integration

- Add direct APNs client using sideshow/apns2 for iOS push
- Add direct FCM client using legacy HTTP API for Android push
- Remove Gorush dependency (no external push server needed)
- Update all services/handlers to use new push.Client
- Update config for APNS_PRODUCTION flag

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

internal/router/router.go

@@ -27,7 +27,7 @@ type Dependencies struct {
 	Config         *config.Config
 	EmailService   *services.EmailService
 	PDFService     *services.PDFService
-	PushClient     interface{} // *push.GorushClient - optional
+	PushClient     *push.Client // Direct APNs/FCM client
 	StorageService *services.StorageService
 }
 
@@ -66,14 +66,6 @@ func SetupRouter(deps *Dependencies) *gin.Engine {
 	notificationRepo := repositories.NewNotificationRepository(deps.DB)
 	subscriptionRepo := repositories.NewSubscriptionRepository(deps.DB)
 
-	// Initialize push client (optional)
-	var gorushClient *push.GorushClient
-	if deps.PushClient != nil {
-		if gc, ok := deps.PushClient.(*push.GorushClient); ok {
-			gorushClient = gc
-		}
-	}
-
 	// Initialize services
 	authService := services.NewAuthService(userRepo, cfg)
 	userService := services.NewUserService(userRepo)
@@ -82,7 +74,7 @@ func SetupRouter(deps *Dependencies) *gin.Engine {
 	taskService := services.NewTaskService(taskRepo, residenceRepo)
 	contractorService := services.NewContractorService(contractorRepo, residenceRepo)
 	documentService := services.NewDocumentService(documentRepo, residenceRepo)
-	notificationService := services.NewNotificationService(notificationRepo, gorushClient)
+	notificationService := services.NewNotificationService(notificationRepo, deps.PushClient)
 
 	// Wire up notification and email services to task service (for task completion notifications)
 	taskService.SetNotificationService(notificationService)
@@ -116,11 +108,7 @@ func SetupRouter(deps *Dependencies) *gin.Engine {
 	// Set up admin routes (separate auth system)
 	adminDeps := &admin.Dependencies{
 		EmailService: deps.EmailService,
-	}
-	if deps.PushClient != nil {
-		if gc, ok := deps.PushClient.(*push.GorushClient); ok {
-			adminDeps.PushClient = gc
-		}
+		PushClient:   deps.PushClient,
 	}
 	admin.SetupRoutes(r, deps.DB, cfg, adminDeps)