fix: count reasoning-only liveness responses as healthy

app/main.py

@@ -654,10 +654,11 @@ def api_check(model_id: str):
             # упадёт, реально потраченные токены сохраняются в checks.
             usage = extract_usage(resp)
             choice = resp["choices"][0]
-            content = choice["message"].get("content")
-            ok = isinstance(content, str) and bool(content.strip())
+            message = choice["message"]
+            ok = any(isinstance(message.get(field), str) and message[field].strip()
+                     for field in ("content", "reasoning_content"))
             if not ok:
-                error = f"Empty text response (finish_reason={choice.get('finish_reason')})"
+                error = f"Empty content and reasoning (finish_reason={choice.get('finish_reason')})"
     except Exception as e:
         error = f"{type(e).__name__}: {e}"
         print(f"[check] {model_id}: {error}")