fix: Enable sync relay discovery in archive_all mode

The bug: SelfSubscriber filtered announcements with lists_our_relay() check,
preventing archive_all mode from discovering relays in announcements that
don't list our relay domain.

The insight: SelfSubscriber only receives events that ALREADY passed
write policy validation (archive_all, archive_whitelist, blacklist, etc.)
via admit_event() before being saved to the database. The event flow:

  External relay → process_event_static() → write_policy.admit_event()
  → (validation happens here) → save to DB → notify_event()
  → SelfSubscriber receives via WebSocket

So the lists_our_relay() check was redundant double-validation that
broke archive_all mode by filtering events that had already been
accepted by the write policy.

The fix: Simply remove the lists_our_relay() filtering. Events reaching
SelfSubscriber are pre-validated and should all be processed for relay
discovery according to the configured archive policy.

Changes:
- Removed lists_our_relay() check from process_notification() (4 lines)
- Removed unused lists_our_relay() helper function (9 lines)
- Added comment explaining events are pre-validated (3 lines)
- Total: 13 lines removed, 3 lines added

Fixes #194d

src/sync/self_subscriber.rs

@@ -148,12 +148,11 @@ impl SelfSubscriber {
     ) -> LoopControl {
         match notification {
             Ok(RelayPoolNotification::Event { event, .. }) => {
-                // Only process 30617 events that list our relay
+                // Process 30617 events for relay discovery
+                // Note: Events reaching here have already passed write policy validation
+                // (archive_all, archive_whitelist, blacklist, etc.) so no additional
+                // filtering is needed.
                 if event.kind == Kind::GitRepoAnnouncement {
-                    if !self.lists_our_relay(&event) {
-                        return LoopControl::Continue;
-                    }
-
                     // Extract repo ID and relays
                     if let Some(repo_id) = Self::extract_repo_id(&event) {
                         let relays = Self::extract_relay_urls(&event);
@@ -251,15 +250,6 @@ impl SelfSubscriber {
         None
     }
 
-    /// Check if announcement lists our relay
-    ///
-    /// Returns true if any extracted relay URL contains our domain
-    fn lists_our_relay(&self, event: &Event) -> bool {
-        Self::extract_relay_urls(event)
-            .iter()
-            .any(|url| url.contains(&self.relay_domain) || url == &self.own_relay_url)
-    }
-
     /// Main run loop
     ///
     /// Connects to own relay, subscribes to relevant event kinds,