fix: use Kimi base URL from env to avoid 401

modules/balance_client.py

@@ -75,7 +75,13 @@ def fetch_kimi_balance() -> Dict[str, Any]:
     if not api_key:
         return {"success": False, "error": "Kimi 密钥未设置（MOONSHOT_API_KEY / API_KEY_KIMI / AGENT_API_KEY）"}
 
-    url = "https://api.moonshot.ai/v1/users/me/balance"
+    base = (
+        _env("API_BASE_KIMI")
+        or _env("MOONSHOT_BASE_URL")
+        or _env("AGENT_API_BASE_URL")
+        or "https://api.moonshot.ai/v1"
+    ).rstrip("/")
+    url = f"{base}/users/me/balance"
     payload, err = _http_get(url, headers={"Authorization": f"Bearer {api_key}"})
     if err:
         return {"success": False, "error": err}