TradeAutonom UserContainer-v2-fr2 Worker

Split-stack container running ONLY the FR-Bot 2 (Spread-Capture
quoter/hedger).

Requests to /u/<user_id>/<path> require a valid X-Internal-Token
header matching the V2_SHARED_TOKEN Worker secret.

Typical usage is indirect: bot.defitool.de proxies /api/fr2/*
here after authenticating the user session and checking the
fr2 enrollment whitelist + user.fr2_backend.