* fix(metadata): prevent stale cross-provider IDs
* fix(metadata): address stale ID review findings
* fix(migrations): build the stale-ID primary key concurrently
ALTER TABLE ... ADD PRIMARY KEY builds the index under ACCESS EXCLUSIVE,
blocking reads and writes on stale_media_ids for the whole build. Create the
wider unique index with CREATE UNIQUE INDEX CONCURRENTLY and attach it with
ADD CONSTRAINT ... PRIMARY KEY USING INDEX instead; all three key columns are
already NOT NULL, so the attach is metadata-only. Same treatment on the
rollback path, plus the repo's INVALID-remnant cleanup so a failed concurrent
build is not silently accepted by IF NOT EXISTS.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---------
Co-authored-by: Quick <31828688+Quick104@users.noreply.github.com>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>
