feat: announcement purgatory

Extends purgatory to hold repository announcements until git data arrives,
preventing empty repositories from being served to clients.

When an announcement is received, a bare repo is created immediately and the
announcement is held in purgatory. It is only promoted and served once a git
push confirms real content exists. If no push arrives before expiry, the bare
repo is deleted and the announcement is silently discarded.

Key behaviours:
- Soft expiry: announcements are hidden from clients but kept alive while git
  pushes are in progress, reviving on successful push
- Expiry is extended when a matching state event or git push is observed
- NIP-09 deletion events remove announcements from purgatory
- Purgatory state (announcements, state events, PR events, expired set) is
  persisted to disk on graceful shutdown and restored on startup, with elapsed
  downtime subtracted from expiry deadlines
- Purgatory announcements drive StateOnly sync in the sync system so state
  events are fetched from listed relays before promotion
- SyncLevel added to RepoSyncIndex to distinguish purgatory repos (StateOnly)
  from promoted repos (Full L2+L3 sync)

1 files changed, 57 insertions, 2 deletions

diff --git a/src/git/authorization.rs b/src/git/authorization.rs
index 27107db..df780bb 100644
--- a/src/git/authorization.rs
+++ b/src/git/authorization.rs
@@ -287,6 +287,39 @@ pub async fn fetch_repository_data(
     })
 }
 
+/// Fetch repository data including announcements from purgatory
+///
+/// This combines database announcements with purgatory announcements,
+/// which is needed for authorization when the announcement hasn't been
+/// promoted yet (no git data has arrived).
+pub async fn fetch_repository_data_with_purgatory(
+    database: &SharedDatabase,
+    purgatory: &crate::purgatory::Purgatory,
+    identifier: &str,
+) -> Result<RepositoryData> {
+    // First, fetch from database
+    let mut repo_data = fetch_repository_data(database, identifier).await?;
+
+    // Then, add announcements from purgatory
+    let purgatory_announcements = purgatory.get_announcements_by_identifier(identifier);
+    let purgatory_count = purgatory_announcements.len();
+
+    for entry in purgatory_announcements {
+        if let Ok(announcement) = RepositoryAnnouncement::from_event(entry.event) {
+            repo_data.announcements.push(announcement);
+        }
+    }
+
+    debug!(
+        "Fetched repository data with purgatory: {} announcements ({} from purgatory), {} states",
+        repo_data.announcements.len(),
+        purgatory_count,
+        repo_data.states.len()
+    );
+
+    Ok(repo_data)
+}
+
 pub fn pubkey_authorised_for_repo_owners(
     pubkey: &PublicKey,
     db_repo_data: &RepositoryData,
@@ -539,8 +572,9 @@ pub async fn get_state_authorization_for_specific_owner_repo(
     use crate::git::list_refs;
     use crate::purgatory::RefUpdate;
 
-    // Fetch announcements only - we don't need database states
-    let repo_data = fetch_repository_data(database, identifier).await?;
+    // Fetch announcements from database AND purgatory - needed for authorization
+    // when the announcement hasn't been promoted yet (no git data has arrived)
+    let repo_data = fetch_repository_data_with_purgatory(database, purgatory, identifier).await?;
 
     if repo_data.announcements.is_empty() {
         return Ok(AuthorizationResult::denied(
@@ -649,6 +683,27 @@ pub async fn get_state_authorization_for_specific_owner_repo(
                         .unwrap_or_else(|_| latest_authorized.pubkey.to_hex())
                 );
 
+                // Extend purgatory announcement expiry for the owner.
+                //
+                // Per design doc decision #4: git auth extending a state event's expiry
+                // also extends the announcement's expiry. The repo is actively receiving
+                // git data, so the announcement should not expire prematurely.
+                // This also revives soft-expired announcements (recreates bare repo).
+                if let Ok(owner_pk) = PublicKey::parse(owner_pubkey) {
+                    if purgatory.has_purgatory_announcement(&owner_pk, identifier) {
+                        purgatory.extend_announcement_expiry(
+                            &owner_pk,
+                            identifier,
+                            std::time::Duration::from_secs(1800),
+                        );
+                        debug!(
+                            identifier = %identifier,
+                            owner = %owner_pubkey,
+                            "Extended purgatory announcement expiry due to git push authorization"
+                        );
+                    }
+                }
+
                 return Ok(AuthorizationResult {
                     authorized: true,
                     reason: "Authorized by state event in purgatory".to_string(),