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, 5 insertions, 5 deletions

diff --git a/grasp-audit/README.md b/grasp-audit/README.md
index 4d2401f..936f10f 100644
--- a/grasp-audit/README.md
+++ b/grasp-audit/README.md
@@ -245,7 +245,7 @@ pub async fn test_something(client: &AuditClient) -> TestResult {
             let ctx = TestContext::new(client);
 
             // 2. Prerequisites (cached per-TestContext)
-            let repo = ctx.get_fixture(FixtureKind::ValidRepo).await?;
+            let repo = ctx.get_fixture(FixtureKind::ValidRepoSent).await?;
 
             // 3. Test-specific event
             let my_event = client.create_issue(&repo, "Title", "Content", vec![])?;
@@ -298,10 +298,10 @@ Fixtures use deterministic commit hashes for reproducible testing:
 
 | Constant                                         | Hash                                       | Used By                                          |
 | ------------------------------------------------ | ------------------------------------------ | ------------------------------------------------ |
-| `DETERMINISTIC_COMMIT_HASH`                      | `64ea71d79a57a7acb334cd9651f8aec067c0ce5d` | Owner fixtures (RepoState, OwnerStateDataPushed) |
-| `MAINTAINER_DETERMINISTIC_COMMIT_HASH`           | `1c2d472c9b71ed51968a66500281a3c4a6840464` | MaintainerStateDataPushed                        |
-| `RECURSIVE_MAINTAINER_DETERMINISTIC_COMMIT_HASH` | `05939b82de66fbdb9c077d0a64fc68522f3cb8e0` | RecursiveMaintainerStateDataPushed               |
-| `PR_TEST_COMMIT_HASH`                            | `5d40fb1555a0c28bf4d650515a73aaa54d4d9bfb` | PR fixtures (PREvent, PREventGenerated)          |
+| `DETERMINISTIC_COMMIT_HASH`                      | `d6e4b26ccf9c268d18d60e6d09804313cc850821` | Owner fixtures (RepoState, OwnerStateDataPushed) |
+| `MAINTAINER_DETERMINISTIC_COMMIT_HASH`           | `d26703c007eff6d17fee3bb70ce8be5d1427d0e7` | MaintainerStateDataPushed                        |
+| `RECURSIVE_MAINTAINER_DETERMINISTIC_COMMIT_HASH` | `54a2b4b3cbc3373ad1438b8ffad1681d12bc6c4a` | RecursiveMaintainerStateDataPushed               |
+| `PR_TEST_COMMIT_HASH`                            | `5a51b30e4615b572dcd5b9e487861b58605a5c21` | PR fixtures (PREvent, PREventGenerated)          |
 
 #### Fixture Dependencies