Document the concurrency regression scenario around two simultaneous payout requests against a limited balance. Acceptance: explain why PostgreSQL row-level locking is the authoritative path; include how to run the existing Django test; note SQLite limitations honestly.
Document the concurrency regression scenario around two simultaneous payout requests against a limited balance. Acceptance: explain why PostgreSQL row-level locking is the authoritative path; include how to run the existing Django test; note SQLite limitations honestly.