Add /api/health endpoint alias for HF Spaces

backend/app.py

@@ -125,6 +125,12 @@ async def health_check():
     }
 
 
+@app.get("/api/health")
+async def api_health_check():
+    """Health check endpoint under /api for HF Spaces compatibility."""
+    return await health_check()
+
+
 @app.post("/api/chat")
 async def chat_endpoint(request: ChatRequest):
     """