Evaluate replacing PeerTransportService's hand-rolled HTTP queue/retry with a thin wrapper around fossil sync for the badge<->canonical-instance leg (Meshtastic keeps its own queue — this only covers networked peers). Demonstrate the project-brief v1 success criteria against the Fossil-backed store: two badges exchange posts over Meshtastic, a public web node forwards public posts, and federation posts are visible on Mastodon.

Acceptance checks: - [ ] Decision recorded (in docs/architecture-decisions.md) on whether badges embed a local fossil process/repo or act as HTTP clients of a remote canonical server (open question #2 in the design doc). - [ ] Decision recorded on single shared canonical Fossil repo vs. per-badge repos (open question #1 in the design doc). - [ ] End-to-end demo: two badge instances exchange a post via the chosen sync path. - [ ] A post authored locally is visible from a real Mastodon account via the ActivityPub bridge (ticket 4). OCX-PLAN: role=work parent=5c25bce48b4a6bef0f14160bab154f28a4dc8f25 seq=2