fix: add root endpoint for HF Spaces health probe

app/api/routes.py

@@ -27,6 +27,14 @@ logger = logging.getLogger(__name__)
 router = APIRouter()
 
 
+# ── Root / HF health probe ──
+
+@router.get("/", tags=["system"])
+async def root():
+    """Root endpoint — HF Spaces probes this URL for health checks."""
+    return {"status": "ok"}
+
+
 # ── Health check ──
 
 @router.get("/health", response_model=HealthResponse, tags=["system"])