Install the image annotation group beside image_favorites and saved_views:
media_annotation_metadata (one row, schema version 1), media_annotation_files
(one private locator per physical file), media_annotation_bytes (one record
per observed SHA-256 with the verified size and mtime_ns) and media_image_tags
(the ordered tag set of a byte record, joined into the global tags registry).
The group migrates in a SAVEPOINT that validates before and after creating
it, with no backfill from prompt or pair tags and no filesystem probe.
annotation_schema_error reads only: it compares the catalog objects after
whitespace compaction, the columns, foreign keys and indexes, and the
persisted values (UUIDs, hex digests, bounds, the 4096-character locator cap
measured past embedded NULs, exactly one metadata row). verify_database_file
checks it with allow_missing=not require_library_state, so old backups
restore and a migrated restore stage must carry it.
Tests pin the exact DDL, a fresh install and idempotent reopen, a current
database without the group gaining it with legacy rows untouched, every
partial or malformed shape rejected without repair, install failure rolling
back and retrying, a WAL backup/restore round trip, staged-failure
immutability of source, live and safety files with every handle closed, and
the require_library_state gate.
