feat(sync): broadcast synced events to WebSocket subscribers

Enable recursive relay discovery by broadcasting synced events to
WebSocket subscribers via LocalRelay.notify_event(). This allows the
SelfSubscriber to receive 30617 announcements synced from external
relays and discover additional relay URLs to connect to.

Changes:
- Pass LocalRelay to SyncManager::new() from main.rs
- Add local_relay field to SyncManager struct
- Call notify_event() after saving synced events to database
- Enable test_recursive_relay_discovery_syncs_announcement test

The test verifies that when relay_a syncs announcement_x from bootstrap
relay_b (which lists relay_c), relay_a discovers and connects to
relay_c to sync announcement_y.

Fixes recursive relay discovery from bootstrap sync.

0 files changed, 0 insertions, 0 deletions