- Extract git commit signatures (gpgsig) during clone, migrate, and pull - Sign git commits on push/sync when a signing key is configured - Add tests for signature preservation and signed push
- Add read-time validation of commit objects in store.rs (verify delta IDs, commit IDs, parent references) - Enable zstd frame checksums on write - Add directory fsync after atomic renames for durability - Validate delta chain consistency in materialize_committed_tree - Reject unsupported Patch delta variants in apply_delta - Defer ref updates in graft to avoid dangling references - Add 'arc check' command (fsck) with orphan detection - Add CorruptObject and UnsupportedDelta error variants
