flutter(rider): rebuild lib on Cubit/Bloc + Tripz backend (core + auth slice)

- keep store identity (com.mobileapp.store.ride, shorebird, firebase, fonts); old lib -> lib_old_getx
- core: config/di/router(go_router)/theme/api_client(dio+tenant+bearer)/token_store(secure)
- auth: repo + AuthCubit + OTP phone/otp screens; home: flutter_map (OSM placeholder, انطلق TODO)
- android usesCleartextTraffic=true for http API; maps=flutter_map (no Google), state=Cubit

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

apps/rider/lib/core/config.dart

@@ -0,0 +1,15 @@
+/// إعداد التطبيق. يُمرَّر عبر --dart-define للنكهات (flavor) لاحقاً.
+class AppConfig {
+  static const String baseUrl = String.fromEnvironment(
+    'BASE_URL',
+    defaultValue: 'http://194.163.173.157:4010/api',
+  );
+
+  /// slug المستأجر (يُبنى لكل نكهة). حالياً: siro.
+  static const String tenantSlug = String.fromEnvironment(
+    'TENANT',
+    defaultValue: 'siro',
+  );
+
+  static const String appName = 'Tripz';
+}