Delete every copy of an explicitly addressed UUID, null version or delete
marker under the pool lock. Preserve retention and replication callbacks,
report unreadable pools and cleanup failures, and keep movement, incoming
replication, expiration and free-version cleanup on their existing paths.
Retain the separately developed general DELETE repair and replace its
access-mover-only coverage with a real interrupted rebalance copy followed
by HTTP deletion. Cover unqualified directory-marker DELETE and document
the existing pool-order-dependent 503 behavior that this makes consistent.
Signed-off-by: Feng Ruohang <rh@vonng.com>
Reverse the first-parent diff of a3df317ae0,
including the feature branch compatibility and mover follow-up fixes.
Retain the independent multi-pool correctness fixes from #178 and migrate
their shared test fixture away from access-tier code.
Tolerate retired ILM keys and XML, read old v9 statistics while writing v8,
and document migration without moving objects or rewriting their metadata.
Include regression coverage using a historical scanner/writer v9 fixture.
Signed-off-by: Feng Ruohang <rh@vonng.com>