xuejourney public resource proxy

Usage:
  /proxy?url=https%3A%2F%2Fexample.com%2Fasset.css
  /fetch?url=https%3A%2F%2Fexample.com%2Fasset.js
  /u/<base64url-url>

Google Fonts compatibility:
  /css2?family=Noto+Sans+SC&display=swap
  /gstatic/...

Limits:
  Methods: GET, HEAD
  Max object: 26214400 bytes
  Timeout: 15000 ms
  Redirects: 3
  Private/internal IP targets are blocked.