Fix secrets download on self-hosted runners: use urllib stdlib instead of requests

.github/workflows/fetch-encrypted-secrets.yml

@@ -19,20 +19,21 @@ jobs:
           retry_wait_seconds: 15
           shell: python
           command: |
-            import requests
             import json
             import time
+            import urllib.request
 
             input_data = json.loads('${{ inputs.zip_url_json }}')
             url = f"{input_data['url']}/get_zip?filename={input_data['file']}"
-            
+
             for attempt in range(5):
                 try:
                     print(f"Downloading (Attempt {attempt + 1})...")
-                    r = requests.get(url, timeout=20)
-                    r.raise_for_status()
+                    # 仅使用标准库（urllib），无需预装 requests，兼容各类 runner 环境
+                    with urllib.request.urlopen(url, timeout=20) as r:
+                        content = r.read()
                     with open('secrets.zip', 'wb') as f:
-                        f.write(r.content)
+                        f.write(content)
                     break
                 except Exception as e:
                     if attempt < 4: