Review round 3 (Codex gpt-5.6-terra) found two concurrent creates of
the same normalised name could both pass the duplicate scan before
either INSERT committed, inserting a duplicate with no warning. The
scan and INSERT now run inside the shared connection-scoped lock, so
the second create always sees the first's committed row and warns.
A gated concurrent-create test proves exactly one warning fires; a
sequential-duplicate warning assertion rode along. Suite: 851 passed.
Joshua King
d5d972b872