MessageRouter outbox drops (attempt cap, TTL expiry in flush and
cleanup, per-peer overflow eviction) now invoke onMessageDropped, wired
to mark the message .failed in the ConversationStore - guarded so a
late failure never downgrades an already delivered/read status.
NostrRelayManager pending subscriptions gain a per-relay cap (64,
oldest-by-sequence eviction; durable intent still replays from
subscriptionRequestState) and a 10-minute age sweep on the existing
connect path. Reconnect backoff gets injectable +/-20% jitter so
recovering relays don't thundering-herd.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
