chore(dashboard): wire up DashboardHandler in server main

Create dashboardHandler instance and add to router config:
- Initialize dashboardHandler using handlers.NewDashboardHandler(queries)
- Add dashboardHandler to router.Config for route registration
- All dashboard routes are now available at /api/dashboard/*

cmd/server/main.go

@@ -119,6 +119,7 @@ func main() {
 
 	// NEW: Create refactored handlers
 	collectionHandler := handlers.NewCollectionHandler(queries, connManager)
+	dashboardHandler := handlers.NewDashboardHandler(queries)
 	mediaHandler := handlers.NewMediaHandler(queries, libraryService, worker)
 	matchingHandler := handlers.NewMatchingHandler(queries, connManager)
 
@@ -168,6 +169,7 @@ func main() {
 		AnalyticsHandler:      analyticsHandler,
 		QueueHandler:          queueHandler,
 		CollectionHandler:     collectionHandler,
+		DashboardHandler:      dashboardHandler,
 		OPDSHandler:           opdsHandler,
 		SystemSettingsHandler: systemSettingsHandler,
 		ConnManager:           connManager,