Makes a Karvan room work between two different phones once they're connected to a pub:
- karvan_model: rooms track remoteFeeds (SSB ids of other participants); addRemoteFeed/
getRemoteFeeds/anyRemoteRooms (feed-id validated, capped at MAX_MEMBERS).
- backend: inviting registers the invitee's feed; joining by link registers the inviter's
feed (read from the invite PM). Posting a message publishes a private 'karvan-relay' to
those feeds; an efficient LIVE log-stream subscriber (createLogStream old:false live:true)
ingests incoming relays and injects them into the local mirror room (dedup by mid,
skips own → no loop). WebRTC SIGNAL frames are NOT relayed (too many/slow for the log).
- Chosen over a muxrpc plugin because a classic pub only replicates the LOG (store-and-forward);
live muxrpc wouldn't reach the other phone. No SSB-startup changes → no boot risk.
Verified: boot OK with the live stream, invite/adopt register feeds, message posts + relay
publishes, server stays up, 16/16 tests. Cross-device delivery needs the user's 2-phone+pub test.
Note: text chat only — video still needs the wrapper camera permission (Fase 3).
6020c7f8df