feat: repoint mobile API to https://imi.khansia.co.id/api/v1

mobile/lib/core/constants/app_constants.dart

-import 'dart:io' show Platform;
-import 'package:flutter/foundation.dart';
-
 class AppConstants {
   static const String appName = 'IMI Jawa Barat';
   static const String appVersion = '1.0.0';
 
-  // Public Ngrok URL for testing on physical mobile devices
-  static const String ngrokBaseUrl = 'https://wilt-process-demanding.ngrok-free.dev/api/v1';
+  // Production domain & API configuration
+  static const String productionBaseUrl = 'https://imi.khansia.co.id/api/v1';
 
   // Base API configuration
   static String get defaultBaseUrl {
-    if (kIsWeb) {
-      return 'http://127.0.0.1:8000/api/v1';
-    }
-    // Default to public ngrok tunnel for physical mobile devices
-    return ngrokBaseUrl;
+    // Default to official production server imi.khansia.co.id for APK & Web
+    return productionBaseUrl;
   }
 
   // Storage keys

mobile/lib/screens/auth/login_screen.dart

@@ -102,12 +102,12 @@ class _LoginScreenState extends State<LoginScreen> {
                       TextField(
                         controller: controller,
                         decoration: const InputDecoration(
-                          hintText: 'http://127.0.0.1:8000/api/v1',
+                          hintText: 'https://imi.khansia.co.id/api/v1',
                         ),
                       ),
                       const SizedBox(height: 10),
                       Text(
-                        'Browser Web: http://127.0.0.1:8000/api/v1\nNgrok / HP: ${AppConstants.ngrokBaseUrl}',
+                        'Default Server: ${AppConstants.productionBaseUrl}\nLokal Server: http://127.0.0.1:8000/api/v1',
                         style: const TextStyle(fontSize: 11, color: AppColors.textMuted),
                       ),
                     ],

mobile/lib/screens/profile/profile_screen.dart

@@ -70,12 +70,12 @@ class _ProfileScreenState extends State<ProfileScreen> {
               TextField(
                 controller: controller,
                 decoration: const InputDecoration(
-                  hintText: 'http://10.0.2.2:8000/api/v1',
+                  hintText: 'https://imi.khansia.co.id/api/v1',
                 ),
               ),
               const SizedBox(height: 10),
               const Text(
-                'Emulator Android gunakan: http://10.0.2.2:8000/api/v1\nHP Fisik gunakan IP LAN komputer: http://192.168.x.x:8000/api/v1',
+                'Default Server: https://imi.khansia.co.id/api/v1\nLokal Server: http://10.0.2.2:8000/api/v1',
                 style: TextStyle(fontSize: 11, color: AppColors.textMuted),
               ),
             ],