fix: replace repo_sync_index wiring with purgatory announcement sync timer

Instead of threading repo_sync_index through PolicyContext/builder.rs/main.rs
to handle user-submitted purgatory announcements, add a simple background
timer (run_purgatory_announcement_sync, every 5s) that scans the purgatory
for announcement entries and registers them in repo_sync_index as StateOnly.

This is simpler and covers both flows:
- Sync-path announcements: inline registration still happens during event
  processing (sync/mod.rs:1839+), timer provides a safety net
- User-submitted announcements: SelfSubscriber never sees them (rejected
  from DB), timer is the primary registration path

The timer calls sync_purgatory_announcements_to_index() which:
1. Snapshots purgatory via new announcements_for_sync() public method
2. Or_inserts StateOnly entries (never downgrades Full entries)
3. Detects newly added relay URLs and calls handle_new_sync_filters to
   connect and subscribe - fixing the failing test that expected relay
   discovery from a user-submitted purgatory announcement

Removes: repo_sync_index field from PolicyContext, set/get_repo_sync_index
methods, set_repo_sync_index on Nip34WritePolicy, wiring in main.rs, and
the inline AcceptPurgatory registration block in builder.rs.

1 files changed, 116 insertions, 9 deletions

diff --git a/src/sync/mod.rs b/src/sync/mod.rs
index 916e2b0..ed5b6e7 100644
--- a/src/sync/mod.rs
+++ b/src/sync/mod.rs
@@ -397,6 +397,37 @@ async fn run_daily_timer(
     }
 }
 
+/// Background task that periodically syncs purgatory announcements into repo_sync_index.
+///
+/// Runs every 5 seconds. For each announcement currently in purgatory, ensures there
+/// is a `StateOnly` entry in `repo_sync_index`. New entries trigger `handle_new_sync_filters`
+/// which connects to the relay URLs listed in the announcement and subscribes to state
+/// events (kind 30618).
+///
+/// This covers two cases:
+/// - Sync-path announcements: registered inline during event processing, but this
+///   provides a safety net in case the inline registration was missed.
+/// - User-submitted purgatory announcements: the SelfSubscriber never sees them
+///   (they're rejected from DB), so this timer is the primary registration path.
+async fn run_purgatory_announcement_sync(
+    sync_manager: Arc<Mutex<SyncManager>>,
+    mut shutdown_rx: broadcast::Receiver<()>,
+) {
+    let interval = Duration::from_secs(5);
+    loop {
+        tokio::select! {
+            _ = tokio::time::sleep(interval) => {
+                let mut manager = sync_manager.lock().await;
+                manager.sync_purgatory_announcements_to_index().await;
+            }
+            _ = shutdown_rx.recv() => {
+                tracing::debug!("Purgatory announcement sync timer received shutdown signal");
+                break;
+            }
+        }
+    }
+}
+
 // Combined Health and Metrics Checker
 
 /// Background task for cleaning up expired entries from the rejected events index
@@ -700,14 +731,6 @@ impl SyncManager {
         self.rejected_events_index.save_to_disk(path)
     }
 
-    /// Get a clone of the repo sync index Arc.
-    ///
-    /// This allows the write policy to register user-submitted purgatory announcements
-    /// in the sync index so that state event sync starts promptly.
-    pub fn repo_sync_index(&self) -> RepoSyncIndex {
-        self.repo_sync_index.clone()
-    }
-
     /// Handle EOSE (End Of Stored Events) for a subscription
     ///
     /// This method:
@@ -1560,7 +1583,17 @@ impl SyncManager {
             run_rejected_index_cleanup(cleanup_manager, cleanup_shutdown).await;
         });
 
-        // 11. Main loop - handle actions from self-subscriber, disconnect, EOSE, and connect notifications
+        // 11. Spawn purgatory announcement sync timer (every 5s)
+        // Ensures purgatory announcements (including user-submitted ones that never
+        // touch the DB) are registered in repo_sync_index as StateOnly so that
+        // state event subscriptions are established on their listed relay URLs.
+        let purgatory_sync_manager = Arc::clone(&sync_manager);
+        let purgatory_sync_shutdown = shutdown_tx.subscribe();
+        tokio::spawn(async move {
+            run_purgatory_announcement_sync(purgatory_sync_manager, purgatory_sync_shutdown).await;
+        });
+
+        // 12. Main loop - handle actions from self-subscriber, disconnect, EOSE, and connect notifications
         loop {
             // Wait for an event without holding the lock
             tokio::select! {
@@ -2419,6 +2452,80 @@ impl SyncManager {
         }
     }
 
+    /// Sync purgatory announcements into repo_sync_index as StateOnly entries.
+    ///
+    /// Called periodically by the purgatory announcement sync timer (every 5s).
+    /// For each announcement currently in purgatory, ensures a `StateOnly` entry
+    /// exists in `repo_sync_index`. New entries are then picked up by
+    /// `handle_new_sync_filters` which connects to listed relay URLs and subscribes
+    /// to state events for that repo.
+    ///
+    /// Idempotent: existing entries are not downgraded (a promoted Full entry stays Full).
+    async fn sync_purgatory_announcements_to_index(&mut self) {
+        use crate::sync::algorithms::{compute_actions, derive_relay_targets};
+
+        // Collect all purgatory announcements (snapshot - no async holds)
+        let announcements = self.purgatory.announcements_for_sync();
+
+        if announcements.is_empty() {
+            return;
+        }
+
+        // Register any new entries in repo_sync_index as StateOnly
+        let mut new_relay_urls: std::collections::HashSet<String> = std::collections::HashSet::new();
+        {
+            let mut index = self.repo_sync_index.write().await;
+            for (repo_id, relays) in &announcements {
+                let entry = index.entry(repo_id.clone()).or_insert_with(|| {
+                    tracing::debug!(
+                        repo_id = %repo_id,
+                        "Registering purgatory announcement in repo_sync_index as StateOnly"
+                    );
+                    RepoSyncNeeds {
+                        relays: std::collections::HashSet::new(),
+                        root_events: std::collections::HashSet::new(),
+                        sync_level: SyncLevel::StateOnly,
+                    }
+                });
+                // Don't downgrade an already-Full entry
+                // Add any new relay URLs
+                for relay in relays {
+                    if entry.relays.insert(relay.clone()) {
+                        new_relay_urls.insert(relay.clone());
+                    }
+                }
+            }
+        }
+
+        if new_relay_urls.is_empty() {
+            return;
+        }
+
+        // For any relay URLs that are new, compute and send AddFilters actions
+        let all_targets = {
+            let repo_index = self.repo_sync_index.read().await;
+            derive_relay_targets(&repo_index)
+        };
+
+        let actions = {
+            let pending_index = self.pending_sync_index.read().await;
+            let relay_index = self.relay_sync_index.read().await;
+            compute_actions(&all_targets, &pending_index, &relay_index)
+        };
+
+        for action in actions {
+            // Only act on relays that have new URLs (avoids redundant work)
+            if new_relay_urls.contains(&action.relay_url) {
+                tracing::info!(
+                    relay = %action.relay_url,
+                    repos = action.items.repos.len(),
+                    "Purgatory sync timer: connecting to new relay from purgatory announcement"
+                );
+                self.handle_new_sync_filters(action).await;
+            }
+        }
+    }
+
     /// Handle a relay disconnection
     ///
     /// This method is called when the event loop terminates and sends a disconnect notification.