feat(build): add dev/staging/prod flavors for client_app + mitra_app

Android product flavors (.dev/.staging suffixes, prod clean) + per-flavor
Dart entrypoints, dart-define env files, and per-flavor Firebase config for
both platforms across 3 projects (halobestie-clone-dev / my-bestie-876ec /
my-bestie-production).

- Android: flavorDimensions("env") + productFlavors; @string/app_name label;
  per-flavor src/<flavor>/google-services.json (clients verified to match each
  applicationId).
- iOS: customer app re-based to the EXISTING App Store identity
  com.asc.hallobestie (dev/staging suffix it; ships as an update to the live
  app). mitra is a new app (com.mybestie.mitra). Per-flavor plists staged in
  ios/config/<flavor>/; Xcode scheme wiring deferred (Mac follow-up).
- firebase_options_{dev,staging,prod}.dart filled with real android + iOS
  values (regenerated from the native config files).
- BUILD_FLAVORS.md per app documents flavor table, build commands, iOS
  identity decision, and the remaining iOS Xcode steps.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client_app/lib/firebase/firebase_options_dev.dart

@@ -1,26 +1,18 @@
-// File generated by FlutterFire CLI.
+// File generated by FlutterFire CLI (regenerated from the registered
+// dev Firebase apps — project halobestie-clone-dev).
 // ignore_for_file: type=lint
 import 'package:firebase_core/firebase_core.dart' show FirebaseOptions;
 import 'package:flutter/foundation.dart'
     show defaultTargetPlatform, kIsWeb, TargetPlatform;
 
-/// Default [FirebaseOptions] for use with your Firebase apps.
-///
-/// Example:
-/// ```dart
-/// import 'firebase_options.dart';
-/// // ...
-/// await Firebase.initializeApp(
-///   options: DefaultFirebaseOptions.currentPlatform,
-/// );
-/// ```
-class DefaultFirebaseOptions {
+/// [FirebaseOptions] for the DEV environment (project halobestie-clone-dev).
+class DevFirebaseOptions {
   static FirebaseOptions get currentPlatform {
     if (kIsWeb) {
-      throw UnsupportedError(
-        'DefaultFirebaseOptions have not been configured for web - '
-        'you can reconfigure this by running the FlutterFire CLI again.',
-      );
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for web - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
     }
     switch (defaultTargetPlatform) {
       case TargetPlatform.android:
@@ -51,7 +43,7 @@ class DefaultFirebaseOptions {
 
   static const FirebaseOptions android = FirebaseOptions(
     apiKey: 'AIzaSyDFWlLSWytqwI7LSdUbVrO7J5De9L2LV2U',
-    appId: '1:1068156046511:android:ba6e699216de1c50b8185a',
+    appId: '1:1068156046511:android:1f589ed358ccdad0b8185a',
     messagingSenderId: '1068156046511',
     projectId: 'halobestie-clone-dev',
     storageBucket: 'halobestie-clone-dev.firebasestorage.app',
@@ -59,10 +51,10 @@ class DefaultFirebaseOptions {
 
   static const FirebaseOptions ios = FirebaseOptions(
     apiKey: 'AIzaSyAQnB5hbj0T5tE4JQZQ9Tx6Whp_u15obMI',
-    appId: '1:1068156046511:ios:c7786cedb9101d34b8185a',
+    appId: '1:1068156046511:ios:bc9098ffc2c2913ab8185a',
     messagingSenderId: '1068156046511',
     projectId: 'halobestie-clone-dev',
     storageBucket: 'halobestie-clone-dev.firebasestorage.app',
-    iosBundleId: 'com.mybestie',
+    iosBundleId: 'com.asc.hallobestie.dev',
   );
 }

client_app/lib/firebase/firebase_options_prod.dart

@@ -0,0 +1,61 @@
+// File generated by FlutterFire CLI (regenerated from the registered
+// prod Firebase apps — project my-bestie-production).
+// ignore_for_file: type=lint
+import 'package:firebase_core/firebase_core.dart' show FirebaseOptions;
+import 'package:flutter/foundation.dart'
+    show defaultTargetPlatform, kIsWeb, TargetPlatform;
+
+/// [FirebaseOptions] for the PROD environment (project my-bestie-production).
+class ProdFirebaseOptions {
+  static FirebaseOptions get currentPlatform {
+    if (kIsWeb) {
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for web - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+    }
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.android:
+        return android;
+      case TargetPlatform.iOS:
+        return ios;
+      case TargetPlatform.macOS:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for macos - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+      case TargetPlatform.windows:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for windows - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+      case TargetPlatform.linux:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for linux - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+      default:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions are not supported for this platform.',
+        );
+    }
+  }
+
+  static const FirebaseOptions android = FirebaseOptions(
+    apiKey: 'AIzaSyAxAp8hcXO-P7HwwVsS3vFe0OX5ZkIyyWI',
+    appId: '1:953866659887:android:55dfbf97ac7c26e7183eda',
+    messagingSenderId: '953866659887',
+    projectId: 'my-bestie-production',
+    storageBucket: 'my-bestie-production.firebasestorage.app',
+  );
+
+  static const FirebaseOptions ios = FirebaseOptions(
+    apiKey: 'AIzaSyA8guPSD87eDLeCsH6jVd1n2_SI4_MaGNE',
+    appId: '1:953866659887:ios:159fd11b1d2f3633183eda',
+    messagingSenderId: '953866659887',
+    projectId: 'my-bestie-production',
+    storageBucket: 'my-bestie-production.firebasestorage.app',
+    iosClientId: '953866659887-bsb3c2a6ir10u47q8vcacre2tmnk59jb.apps.googleusercontent.com',
+    iosBundleId: 'com.asc.hallobestie',
+  );
+}

client_app/lib/firebase/firebase_options_staging.dart

@@ -0,0 +1,61 @@
+// File generated by FlutterFire CLI (regenerated from the registered
+// staging Firebase apps — project my-bestie-876ec).
+// ignore_for_file: type=lint
+import 'package:firebase_core/firebase_core.dart' show FirebaseOptions;
+import 'package:flutter/foundation.dart'
+    show defaultTargetPlatform, kIsWeb, TargetPlatform;
+
+/// [FirebaseOptions] for the STAGING environment (project my-bestie-876ec).
+class StagingFirebaseOptions {
+  static FirebaseOptions get currentPlatform {
+    if (kIsWeb) {
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for web - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+    }
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.android:
+        return android;
+      case TargetPlatform.iOS:
+        return ios;
+      case TargetPlatform.macOS:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for macos - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+      case TargetPlatform.windows:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for windows - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+      case TargetPlatform.linux:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions have not been configured for linux - '
+          'you can reconfigure this by running the FlutterFire CLI again.',
+        );
+      default:
+        throw UnsupportedError(
+          'DefaultFirebaseOptions are not supported for this platform.',
+        );
+    }
+  }
+
+  static const FirebaseOptions android = FirebaseOptions(
+    apiKey: 'AIzaSyAOPkPJkHXLFzo9ICOHyjee2Vn_EUqt1Pc',
+    appId: '1:650461407929:android:05754df9552e0529504968',
+    messagingSenderId: '650461407929',
+    projectId: 'my-bestie-876ec',
+    storageBucket: 'my-bestie-876ec.firebasestorage.app',
+  );
+
+  static const FirebaseOptions ios = FirebaseOptions(
+    apiKey: 'AIzaSyC_BewS88iaNsc9QdwsPzkV0sf9wUs4i_4',
+    appId: '1:650461407929:ios:4ee79d479b69d688504968',
+    messagingSenderId: '650461407929',
+    projectId: 'my-bestie-876ec',
+    storageBucket: 'my-bestie-876ec.firebasestorage.app',
+    iosClientId: '650461407929-fb4t48nmguaslfvis7ebsea8vndro7ac.apps.googleusercontent.com',
+    iosBundleId: 'com.asc.hallobestie.staging',
+  );
+}

client_app/lib/main.dart

@@ -13,10 +13,23 @@ import 'core/chat/chat_notifier.dart';
 import 'core/notifications/notification_service.dart';
 import 'core/pairing/pairing_notifier.dart';
 import 'core/theme/halo_theme.dart';
-import 'firebase_options.dart';
+import 'firebase/firebase_options_dev.dart';
 import 'router.dart';
 
-void main() async {
+/// Shared app bootstrap, parameterised per build flavor.
+///
+/// The flavor entrypoints (`main_dev.dart`, `main_staging.dart`,
+/// `main_prod.dart`) each call this with their environment's
+/// [FirebaseOptions] and a [flavor] tag. The bare [main] below delegates to
+/// dev so a plain `flutter run` (no `-t`) still launches the dev environment.
+///
+/// `flavor` is currently informational (kept on hand for future flavor-gated
+/// behaviour / analytics tagging); the API base URL is supplied separately via
+/// `--dart-define-from-file=env/<flavor>.json` (see BUILD_FLAVORS.md).
+Future<void> bootstrap({
+  required FirebaseOptions firebaseOptions,
+  required String flavor,
+}) async {
   WidgetsFlutterBinding.ensureInitialized();
 
   // Pre-warm flutter_secure_storage. The first call triggers AndroidX
@@ -26,7 +39,7 @@ void main() async {
   // splash instead of paying it on the user's first interaction.
   unawaited(TokenStorage().readRefreshToken());
 
-  await Firebase.initializeApp(options: DefaultFirebaseOptions.currentPlatform);
+  await Firebase.initializeApp(options: firebaseOptions);
 
   final messaging = FirebaseMessaging.instance;
   await messaging.requestPermission();
@@ -34,6 +47,16 @@ void main() async {
   runApp(const ProviderScope(child: App()));
 }
 
+void main() async {
+  // Bare `flutter run` (no `-t lib/main_<flavor>.dart`) defaults to dev so
+  // local development works out of the box. Build-flavor APKs use the
+  // flavor-specific entrypoints instead.
+  await bootstrap(
+    firebaseOptions: DevFirebaseOptions.currentPlatform,
+    flavor: 'dev',
+  );
+}
+
 class App extends ConsumerStatefulWidget {
   const App({super.key});
 

client_app/lib/main_dev.dart

@@ -0,0 +1,14 @@
+import 'firebase/firebase_options_dev.dart';
+import 'main.dart';
+
+/// DEV flavor entrypoint.
+///
+/// Run/build with the matching flavor + env file:
+///   flutter run --flavor dev -t lib/main_dev.dart \
+///     --dart-define-from-file=env/dev.json
+void main() {
+  bootstrap(
+    firebaseOptions: DevFirebaseOptions.currentPlatform,
+    flavor: 'dev',
+  );
+}

client_app/lib/main_prod.dart

@@ -0,0 +1,14 @@
+import 'firebase/firebase_options_prod.dart';
+import 'main.dart';
+
+/// PROD flavor entrypoint.
+///
+/// Run/build with the matching flavor + env file:
+///   flutter build apk --flavor prod -t lib/main_prod.dart \
+///     --dart-define-from-file=env/prod.json
+void main() {
+  bootstrap(
+    firebaseOptions: ProdFirebaseOptions.currentPlatform,
+    flavor: 'prod',
+  );
+}

client_app/lib/main_staging.dart

@@ -0,0 +1,14 @@
+import 'firebase/firebase_options_staging.dart';
+import 'main.dart';
+
+/// STAGING flavor entrypoint.
+///
+/// Run/build with the matching flavor + env file:
+///   flutter run --flavor staging -t lib/main_staging.dart \
+///     --dart-define-from-file=env/staging.json
+void main() {
+  bootstrap(
+    firebaseOptions: StagingFirebaseOptions.currentPlatform,
+    flavor: 'staging',
+  );
+}