feat: add RouteGuard for authentication

lib/src/standards/route_guard.dart

@@ -0,0 +1,45 @@
+import 'package:get/get.dart';
+import 'package:mom_kitchen/src/standards/app_pages.dart';
+import 'package:mom_kitchen/src/controllers/profile_controller.dart';
+
+enum AuthLevel { none, optional, required }
+
+class RouteGuard {
+  static bool canAccess(String route, {String? userId}) {
+    final pageInfo = PageRegistry.getPage(route);
+    if (pageInfo == null) return false;
+
+    final authLevel = pageInfo.metadata?['authLevel'] as AuthLevel? ?? AuthLevel.none;
+
+    switch (authLevel) {
+      case AuthLevel.none:
+        return true;
+      case AuthLevel.optional:
+        return true;
+      case AuthLevel.required:
+        return userId != null && userId.isNotEmpty;
+    }
+  }
+
+  static String? getRedirectRoute(String route, {String? userId}) {
+    if (canAccess(route, userId: userId)) return null;
+
+    return '/login';
+  }
+
+  static Future<bool> checkAuth(String route) async {
+    final profileController = Get.find<ProfileController>();
+    await profileController.checkLoginStatus();
+
+    final userId = profileController.user.value?.id;
+    return canAccess(route, userId: userId);
+  }
+
+  static Future<String?> getAuthRedirect(String route) async {
+    final profileController = Get.find<ProfileController>();
+    await profileController.checkLoginStatus();
+
+    final userId = profileController.user.value?.id;
+    return getRedirectRoute(route, userId: userId);
+  }
+}