Phase 2 refinements: Firebase config, dev environment fixes, phase 3 requirement draft

- Integrated Firebase SDK in both Flutter apps (google-services, firebase_options)
- Fixed auth flow, API client, and pairing/status blocs for dev environment
- Added full Flutter project scaffolds (android, ios, web, etc.)
- Added phase 3 chat engine requirement document
- Added bugreport zip pattern to gitignore

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

client_app/lib/core/auth/auth_bloc.dart

@@ -91,11 +91,10 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
     final prefs = await SharedPreferences.getInstance();
     final customerId = prefs.getString('anonymous_customer_id');
     final displayName = prefs.getString('anonymous_display_name');
+    final currentUser = _auth.currentUser;
 
-    if (_auth.currentUser != null) {
-      await _verifyAndEmit(emit);
-    } else if (customerId != null && displayName != null) {
-      // Check anonymity config
+    if (currentUser != null && currentUser.isAnonymous && customerId != null && displayName != null) {
+      // Anonymous Firebase user — restore anonymous state
       try {
         final config = await apiClient.get('/api/shared/config/anonymity');
         final anonymityEnabled = config['data']['anonymity_enabled'] as bool;
@@ -107,6 +106,9 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
       } catch (_) {
         emit(AuthAnonymous(customerId: customerId, displayName: displayName));
       }
+    } else if (currentUser != null && !currentUser.isAnonymous) {
+      // Fully registered Firebase user
+      await _verifyAndEmit(emit);
     } else {
       emit(AuthInitial());
     }
@@ -115,6 +117,10 @@ class AuthBloc extends Bloc<AuthEvent, AuthState> {
   Future<void> _onAnonymousLogin(AnonymousLoginRequested event, Emitter<AuthState> emit) async {
     emit(AuthLoading());
     try {
+      // Sign in anonymously with Firebase to get a real JWT
+      await _auth.signInAnonymously();
+
+      // Create/get customer record on backend linked to this Firebase UID
       final response = await apiClient.post(
         '/api/shared/customer/anonymous',
         data: {'display_name': event.displayName},