## Checklist

- [ ] If you changed **decentralized STUN** logic: update **both** `electron/src/stun-bootstrap.ts` and `src/lib/webrtc/stunBootstrap.ts` together, and run `npm test` (includes `stunBootstrap` golden + `electron/src/stun-udp-server.test.ts`).

## Description

<!-- What does this PR change and why? -->