Add `npm run docker:tunnel` (docker-compose.tunnel.yml overlay): a
cloudflared sidecar opens a public quick tunnel to the backend, and the
backend auto-discovers its https://…trycloudflare.com URL from cloudflared's
metrics endpoint (services/relay-url.ts) and bakes it into the wallet-import
QR — so a phone on any network can scan, with no install/account/PUBLIC_RELAY_URL.
PUBLIC_RELAY_URL still wins when set. Verified end-to-end: the backend logs
the discovered tunnel URL on startup.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Khalid Abdi