refactor core providers

app/lib/core/providers/router.dart

@@ -0,0 +1,11 @@
+import 'package:go_router/go_router.dart';
+import 'package:hooks_riverpod/hooks_riverpod.dart';
+import 'package:lensai/core/routing/routes.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'router.g.dart';
+
+@Riverpod(keepAlive: true)
+GoRouter router(Ref ref) {
+  return GoRouter(debugLogDiagnostics: true, routes: $appRoutes);
+}