The relay was failing because processCreateEvent relied on the friends
table to discover the DM recipient, but friendships aren't federated
across instances. Also, resolveLocalUser matched deleted replicated
users before active ones.
- Add participants[] to FederationRelayEvent with homeUserId/homeInstance
for all DM channel members
- Add getDmParticipants() helper to look up member identities
- Include participants in outbox payloads (create/update) and sync events
- Rewrite processCreateEvent to resolve participants directly, compute
canonicalDmPairId, and findOrCreateDmChannel — removing the entire
friends-list fallback (60+ lines)
- Fix resolveLocalUser to filter out deleted users (is_deleted = 0)
and prefer the replicated user match when multiple candidates exist