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, 4 insertions, 2 deletions

diff --git a/grasp-audit/src/specs/grasp01/mod.rs b/grasp-audit/src/specs/grasp01/mod.rs
index 0a819ee..1694f58 100644
--- a/grasp-audit/src/specs/grasp01/mod.rs
+++ b/grasp-audit/src/specs/grasp01/mod.rs
@@ -19,6 +19,7 @@ pub mod git_clone;
 pub mod git_filter;
 pub mod nip01_smoke;
 pub mod nip11_document;
+pub mod purgatory;
 pub mod push_authorization;
 pub mod repository_creation;
 pub mod spec_requirements;
@@ -29,9 +30,10 @@ pub use git_clone::GitCloneTests;
 pub use git_filter::GitFilterTests;
 pub use nip01_smoke::Nip01SmokeTests;
 pub use nip11_document::Nip11DocumentTests;
+pub use purgatory::PurgatoryTests;
 pub use push_authorization::PushAuthorizationTests;
 pub use repository_creation::RepositoryCreationTests;
 pub use spec_requirements::{
-    get_requirement, get_requirements_for_section, get_sections, RequirementLevel, SpecRequirement,
-    GRASP_01_REQUIREMENTS, GRASP_COMMIT_ID,
+    get_requirement, get_requirement_by_ref, get_requirements_for_section, get_sections,
+    RequirementLevel, SpecRef, SpecRequirement, GRASP_01_REQUIREMENTS, GRASP_COMMIT_ID,
 };