POLISHING STUFF and Smarter AI, and alot i mean.. ALOT OF BUG FIX AND OPTIMIZE

walkguide-mobile/walkguide_app/lib/core/constants/app_constants.dart

@@ -1,7 +1,8 @@
 import 'package:shared_preferences/shared_preferences.dart';
 
 class AppConstants {
-  static const String defaultServerUrl = 'http://202.46.28.170:8080';
+  static const String defaultServerUrl = 'http://127.0.0.1:8080';
+  static const String publicServerUrl = 'http://202.46.28.170:8080';
   static const String _serverUrlKey = 'server_base_url';
   static const String _selectedYoloModelKey = 'selected_yolo_model';
 
@@ -10,7 +11,7 @@ class AppConstants {
     final prefs = await SharedPreferences.getInstance();
     final saved = prefs.getString(_serverUrlKey);
     if (saved == null || saved.trim().isEmpty) {
-      return defaultServerUrl;
+      return null;
     }
     return saved;
   }
@@ -38,7 +39,7 @@ class AppConstants {
 
   static Future<void> clearServerUrl() async {
     final prefs = await SharedPreferences.getInstance();
-    await prefs.setString(_serverUrlKey, defaultServerUrl);
+    await prefs.remove(_serverUrlKey);
   }
 
   static String buildApiUrl(String baseUrl) => '$baseUrl/api/v1';