ci / vet-and-test (pull_request) Successful in 42s
Why: with _txlock=immediate the whole migration pass holds the write lock; four racing migrators on a slow CI disk exceeded the 5s busy timeout (job 2285: SQLITE_BUSY in TestMigrateRacingSQLite) although the local tier passes. Evidence: go test -count=3 on the migration atomicity suite green locally; CI failure log cited in the Dev PR. Impact: local SQLite tier only - lock contention waits up to 30s instead of erroring; no schema or API change. Refs: Dev PR #325; plan KTD8.