fix: add health endpoint to chat stable router for debugging

- Add simple health check endpoint at /api/v1/chat/health
- Helps verify if router is properly loaded in production

src/api/routes/chat_stable.py

@@ -18,6 +18,11 @@ from src.services.chat_data_integration import chat_data_integration
 
 router = APIRouter(prefix="/api/v1/chat")
 
+@router.get("/health")
+async def chat_stable_health():
+    """Simple health check for chat stable router"""
+    return {"status": "ok", "router": "chat_stable", "portal_integration": "enabled"}
+
 # Initialize services with lazy loading
 maritaca_client = None
 intent_detector = None