This series fixes two related inconsistencies around secondary-index
names.
1. `DESCRIBE INDEX ... WITH INTERNALS` returned the backing
materialized-view name in the `name` column instead of the logical
index name.
2. The snapshot REST API accepted backing table names for MV-backed
secondary indexes, but not the logical index names exposed to users.
The snapshot side now resolves logical secondary-index names to backing
table names where applicable, reports logical index names in snapshot
details, rejects vector index names with HTTP 400, and keeps multi-keyspace
DELETE atomic by resolving all keyspaces before deleting anything.
The tests were also extended accordingly, and the snapshot test helper
was fixed to clean up multi-table snapshots using one DELETE per table.
Fixes: SCYLLADB-1122
Minor bugfix, no need to backport.
Closesscylladb/scylladb#29083
* github.com:scylladb/scylladb:
cql3: fix DESCRIBE INDEX WITH INTERNALS name
test: add snapshot REST API tests for logical index names
test: fix snapshot cleanup helper
api: clarify snapshot REST parameter descriptions
api: surface no_such_column_family as HTTP 400
db: fix clear_snapshot() atomicity and use C++23 lambda form
db: normalize index names in get_snapshot_details()
db: add resolve_table_name() to snapshot_ctl
a8bc90a375