v0.5.3

Fixed

• Preserved checkpoint-owned cache images while copy-on-write snapshot reclaim,
  DB-wide GC, direct blob deletes, or write-through paths run concurrently.
  This fixes NoKV-style metadata pressure that could otherwise report
  snapshot_dirty_versions: dirty entry lost cache image or
  write_through_batch: flushing entry lost cache image.
• Kept direct write-through from retiring another in-flight checkpoint epoch;
  it now clears only unclaimed dirty state and leaves flushing ownership intact.

Validation

• cargo fmt --all -- --check
• cargo clippy --workspace --all-targets -- -D warnings
• cargo test store::buffer_manager::tests -- --nocapture
• NoKV sibling FUSE/RustFS/JuiceFS smoke with local Holt patch completed without
  checkpoint invariant failures.