refactor(router): check auto_scan_enabled before starting watch mode

- Add check for auto_scan_enabled setting in router before starting watch mode
- Update StartScanner handler to verify auto-scan is enabled
- Switch scanner to use watchModeCtx/watchModeCancel instead of ctx/cancel
- Update StartWatchModeForLibrary to use new MediaScanner signature

internal/handlers/scanner.go

@@ -136,7 +136,10 @@ func (h *Handler) StartScanner(c echo.Context) error {
 	h.scanner.SetAdminID(pgtype.UUID{Bytes: userUUID, Valid: true})
 
 	// Start watching for changes
-	h.scanner.WatchChanges(h.ctx)
+	if !h.scanner.GetAutoScanEnabled() {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "auto-scan disabled in settings"})
+	}
+	h.scanner.WatchChanges(h.watchModeCtx)
 
 	return c.JSON(http.StatusOK, map[string]string{"message": "scanner started"})
 }
@@ -146,8 +149,8 @@ func (h *Handler) StopScanner(c echo.Context) error {
 	h.mu.Lock()
 	defer h.mu.Unlock()
 
-	h.cancel()
-	h.ctx, h.cancel = context.WithCancel(context.Background())
+	h.watchModeCancel()
+	h.watchModeCtx, h.watchModeCancel = context.WithCancel(context.Background())
 
 	return c.JSON(http.StatusOK, map[string]string{"message": "scanner stopped"})
 }
@@ -197,7 +200,7 @@ func (h *Handler) StartWatchModeForLibrary(ctx context.Context, libraryID pgtype
 		folderPaths[i] = folder.FolderPath
 	}
 
-	scanner := services.NewMediaScanner(h.db, 3)
+	scanner := services.NewMediaScanner(h.db)
 	if err := scanner.SetFolders(folderPaths); err != nil {
 		return fmt.Errorf("failed to set scanner folders: %v", err)
 	}
@@ -329,24 +332,3 @@ func (h *Handler) StartWatchModeForAllLibraries(ctx context.Context) error {
 
 	return nil
 }
-
-// StartScheduler starts the auto-scan scheduler
-func (h *Handler) StartScheduler() {
-	h.scheduler.Start()
-}
-
-// StopScheduler stops the auto-scan scheduler
-func (h *Handler) StopScheduler() {
-	h.scheduler.Stop()
-	h.worker.Shutdown()
-
-	// Stop the sync queue processor
-	if h.queueCancel != nil {
-		h.queueCancel()
-	}
-
-	// Stop connection manager cleanup task
-	if h.cleanupTaskCancel != nil {
-		h.cleanupTaskCancel()
-	}
-}