feat: finalize AI analyzer, sync endpoints, and stabilize builds

walkguide-mobile/walkguide_app/lib/core/services/call_service.dart

@@ -20,7 +20,7 @@ class CallService {
   }
 
   Future<int?> getPairedReceiverId() async {
-    final res = await _apiClient.dio.get('/pairing/status');
+    final res = await _apiClient.dio.get('/shared/pairing/status');
     final data = res.data['data'];
     if (data is! Map<String, dynamic>) return null;
     final id = data['pairedWithId'];
@@ -72,6 +72,10 @@ class CallService {
     int uid = 0,
   }) async {
     try {
+      if (AppConstants.agoraAppId.isEmpty) {
+        debugPrint('Agora join skipped: AGORA_APP_ID is not configured');
+        return false;
+      }
       _engine ??= createAgoraRtcEngine();
       await _engine!.initialize(const RtcEngineContext(appId: AppConstants.agoraAppId));
       await _engine!.enableAudio();