Multi-Sub Merger (Cloudflare Worker)

Usage:
  GET /sub  -> merged subscription (base64 encoded, one node per line)

Environment variables (comma/newline/semicolon separated):
  NODES - direct node links (vmess://, ss://, vless://, trojan:// ...)
  SUBS  - subscription URLs (content is base64-decoded, then parsed line by line)
  LINKS - mixed list, auto-detected (http(s):// -> subscription, else node)