feat(config): gate Firebase behind WEBTRIT_APP_FIREBASE_ENABLED

Add a WEBTRIT_APP_FIREBASE_ENABLED config (default true, runtime-overridable
via EnvRegistry) that gates every Firebase touchpoint in bootstrap: Firebase
app, messaging and local pushes init, the app-id provider (FirebaseAppIdProvider
vs SharedPreferencesAppIdProvider), and Remote Config (falls back to the local
shared-preferences cache when off). The analytics repository is now provided
lazily and its navigator observer is only attached when the flag is on, so the
app never touches FirebaseAnalytics.instance when Firebase is disabled.

This lets a host that owns the default Firebase app - the theme configurator's
realtime preview - run the embedded app Firebase-free by configuring the flag
off, while standalone builds default to true and behave exactly as before.

Author: SERDUN

dart_define.json

@@ -1,4 +1,6 @@
 {
+  "WEBTRIT_APP_FIREBASE_ENABLED": true,
+  "__WEBTRIT_APP_FIREBASE_ENABLED_DESCRIPTION": "Whether Firebase (app, messaging, local push, Remote Config, Installations, Analytics) is initialised. Default true. Disable when the app is embedded in a host that owns the default Firebase app (e.g. the theme configurator's realtime preview) so the embedded app runs Firebase-free.",
   "WEBTRIT_APP_DATABASE_LOG_STATEMENTS": false,
   "_WEBTRIT_APP_CORE_URL": "",
   "WEBTRIT_APP_DEMO_CORE_URL": "http://192.168.10.100:4000",

docs/environment.md

@@ -36,6 +36,8 @@ maintainability and enabling tools to parse configuration reliably.
 - `WEBTRIT_APP_DEMO_CORE_URL` – Demo core URL (_default: **http://localhost:4000**_).
 - `WEBTRIT_APP_DATABASE_LOG_STATEMENTS` – Enables logging of database queries (
   _default: **false**_).
+- `WEBTRIT_APP_FIREBASE_ENABLED` – Whether Firebase is initialised (_default: **true**_). Set to
+  `false` to run embedded in a host that owns the default Firebase app (configurator realtime preview).
 - `_WEBTRIT_APP_CORE_URL` – Custom core URL (optional override).
 - `_WEBTRIT_APP_CORE_VERSION_CONSTRAINT` – Core compatibility range.
 - `_WEBTRIT_APP_ABOUT_URL` – URL for "About" screen content.

lib/app/view/app.dart

@@ -147,7 +147,7 @@ class _AppState extends State<App> {
                   deepLinkBuilder: isDeepLinkEnabled ? appRouter.deepLinkBuilder : null,
                   navigatorObservers: () => [
                     AppRouterObserver(),
-                    context.read<AppAnalyticsRepository>().createObserver(),
+                    if (EnvironmentConfig.FIREBASE_ENABLED) context.read<AppAnalyticsRepository>().createObserver(),
                     AutoRouteObserver(),
                   ],
                   reevaluateListenable: ReevaluateListenable.stream(

lib/bootstrap.dart

@@ -42,17 +42,27 @@ IsolateContext? _isolateContext;
 Future<InstanceRegistry> bootstrap() async {
   final registry = InstanceRegistry();
 
-  // External SDKs (Side effects only, don't need registration)
-  await _initFirebaseApp();
-  await _initFirebaseMessaging();
-  await _initLocalPushs();
+  // External SDKs (Side effects only, don't need registration). Gated by the
+  // WEBTRIT_APP_FIREBASE_ENABLED config so a host that owns the default Firebase
+  // app (e.g. the theme configurator's realtime preview) can run this app
+  // Firebase-free by configuring that flag off.
+  final firebaseEnabled = EnvironmentConfig.FIREBASE_ENABLED;
+  if (firebaseEnabled) {
+    await _initFirebaseApp();
+    await _initFirebaseMessaging();
+    await _initLocalPushs();
+  }
 
   // Initialize Components
 
   // App Info & Device Data
 
   final packageInfo = await PackageInfoFactory.init();
-  final appInfo = await AppInfo.init(FirebaseAppIdProvider());
+  // FirebaseAppIdProvider uses Firebase Installations; without Firebase use the
+  // local shared-preferences id provider instead.
+  final appInfo = await AppInfo.init(
+    firebaseEnabled ? FirebaseAppIdProvider() : const SharedPreferencesAppIdProvider(),
+  );
   final deviceInfo = await DeviceInfoFactory.init();
 
   // Storages
@@ -97,9 +107,21 @@ Future<InstanceRegistry> bootstrap() async {
     apiClientFactory: apiClientFactory,
   );
 
-  // Remote configuration
+  // Remote configuration. Firebase Remote Config needs the Firebase app, so when
+  // Firebase is disabled fall back to the local shared-preferences cache
+  // (DefaultRemoteCacheConfigService also implements RemoteConfigService).
   final remoteCacheConfigService = await DefaultRemoteCacheConfigService.init();
-  final cachedRemoteConfigService = await CachedRemoteConfigService.init(remoteCacheConfigService);
+  RemoteConfigService cachedRemoteConfigService;
+  if (firebaseEnabled) {
+    try {
+      cachedRemoteConfigService = await CachedRemoteConfigService.init(remoteCacheConfigService);
+    } catch (e, s) {
+      Logger('bootstrap').warning('Firebase Remote Config init failed; using local cache fallback', e, s);
+      cachedRemoteConfigService = remoteCacheConfigService;
+    }
+  } else {
+    cachedRemoteConfigService = remoteCacheConfigService;
+  }
 
   final featureAccessStreamFactory = FeatureAccessStreamFactory(
     appThemes: appThemes,

lib/environment_config.dart

@@ -47,6 +47,14 @@ class EnvironmentConfig {
     return seconds > 0 ? seconds : compileTime;
   }
 
+  // Whether Firebase (app, messaging, local push, Remote Config, Installations,
+  // Analytics) is initialised. Disable it when this app is embedded in a host
+  // that owns the default Firebase app (the theme configurator's realtime
+  // preview), so the embedded app runs Firebase-free.
+  static const FIREBASE_ENABLED__NAME = 'WEBTRIT_APP_FIREBASE_ENABLED';
+  static bool get FIREBASE_ENABLED =>
+      _env.boolean(FIREBASE_ENABLED__NAME, const bool.fromEnvironment(FIREBASE_ENABLED__NAME, defaultValue: true));
+
   static const DATABASE_LOG_STATEMENTS__NAME = 'WEBTRIT_APP_DATABASE_LOG_STATEMENTS';
   static bool get DATABASE_LOG_STATEMENTS => _env.boolean(
     DATABASE_LOG_STATEMENTS__NAME,

lib/main.dart

@@ -147,7 +147,13 @@ class RootApp extends StatelessWidget {
                 create: (_) => instanceRegistry.get(),
                 dispose: disposeIfDisposable,
               ),
-              RepositoryProvider.value(value: AppAnalyticsRepository(instance: FirebaseAnalytics.instance)),
+              // Lazy so the FirebaseAnalytics.instance handle is created only when the
+              // analytics observer is actually attached. With WEBTRIT_APP_FIREBASE_ENABLED
+              // false the observer is skipped (see App), so this provider is never read and
+              // the embedded app stays Firebase-free.
+              RepositoryProvider<AppAnalyticsRepository>(
+                create: (_) => AppAnalyticsRepository(instance: FirebaseAnalytics.instance),
+              ),
               RepositoryProvider<RegisterStatusRepository>.value(value: registerStatusRepository),
               RepositoryProvider<PresenceSettingsRepository>.value(value: presenceSettingsRepository),
               RepositoryProvider<QueuedTerminationRequestsRepository>.value(value: queuedTerminationRequestsRepository),

test/environment_config_test.dart

@@ -91,5 +91,15 @@ void main() {
       EnvironmentConfig.applyOverrides({name: '30'});
       expect(EnvironmentConfig.USER_REPOSITORY_POLLING_INTERVAL_SECONDS, 30);
     });
+
+    test('FIREBASE_ENABLED defaults to true and reflects a false override', () {
+      expect(EnvironmentConfig.FIREBASE_ENABLED, isTrue);
+
+      EnvironmentConfig.applyOverrides({EnvironmentConfig.FIREBASE_ENABLED__NAME: 'false'});
+      expect(EnvironmentConfig.FIREBASE_ENABLED, isFalse);
+
+      EnvironmentConfig.clearOverrides();
+      expect(EnvironmentConfig.FIREBASE_ENABLED, isTrue);
+    });
   });
 }