A failed fire-and-forget event left one peer's active call state divergent until
some later discovery or reconnect happened. During a LAN party that could leave
different players looking at different rosters or chat.
Fall back to the existing bidirectional handshake whenever a live Call to Play
send fails. Its active-history exchange heals both sides immediately when the
failure was transient. Document the related wall-clock synchronization
assumption for deadline and countdown presentation.
Test Plan:
- `just fmt` -- passed
- `just clippy` -- passed
- `just test` -- passed, 147 peer tests
- `just peer-cli-tests S48` -- passed
- `git diff --cached --check` -- passed