feat: implement production flavor with environment configuration and build support

lib/config/app_config.dart

@@ -1,6 +1,6 @@
 import 'package:flutter_dotenv/flutter_dotenv.dart';
 
-enum Flavor { local, demo, dev }
+enum Flavor { local, demo, dev, prod }
 
 class AppConfig {
   static late Flavor flavor;
@@ -13,5 +13,4 @@ class AppConfig {
   }
 
   static String get apiBaseUrl => dotenv.env['API_BASE_URL'] ?? '';
-  static String get storageBaseUrl => dotenv.env['STORAGE_BASE_URL'] ?? '';
 }

lib/main_prod.dart

@@ -0,0 +1,4 @@
+import 'package:real_estate_mobile/config/app_config.dart';
+import 'package:real_estate_mobile/main.dart';
+
+void main() => mainCommon(Flavor.prod);