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.

1 files changed, 0 insertions, 5 deletions

diff --git a/tests/sync/discovery.rs b/tests/sync/discovery.rs
index 3cdf00d..9e27f9e 100644
--- a/tests/sync/discovery.rs
+++ b/tests/sync/discovery.rs
@@ -293,12 +293,7 @@ async fn test_layer2_discovery_with_chain() {
 /// 3. Discovers and connects to relay_c
 /// 4. Syncs announcement_y from relay_c
 ///
-/// NOTE: This test is ignored because recursive relay discovery from synced
-/// announcements is not yet implemented. Currently, discovery only triggers
-/// when an announcement is directly submitted to a relay, not when it's
-/// synced from a bootstrap relay.
 #[tokio::test]
-#[ignore = "Recursive relay discovery from bootstrap sync not yet implemented"]
 async fn test_recursive_relay_discovery_syncs_announcement() {
     // 1. Start all three relays