Replace timestamp-based catch-up with proper set reconciliation.
When a peer joins a room it publishes its full filename inventory.
Other peers diff against their own set and re-publish only the
events the newcomer is missing, then send their own inventory so
the newcomer can do the same. Two rounds max, no infinite loops.
Also switched from custom #channel tag (rejected by relays as
unindexed) to standard #t topic tag, and kind 4078 to kind 1.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Fifth library variant that keeps folder sync for offline/local use
AND adds Nostr relay sync for cross-device reach via WebSocket.
Both transports run simultaneously - writes go to folder AND Nostr,
sync imports from both and bridges events between them.
Works from file:// since Nostr uses WebSocket (not fetch/WebRTC).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
