Why: creating an account and its activation key, and changing a password, were separate commits, so a crash could leave a user without a key or a new password with a still-valid login key.
Evidence: SELF go test ./internal/store including TestConcurrentCreateOneWinner, TestPasswordChangeIsAtomic, TestOpenExistingDoesNotMigrateOrCreate, and TestBootstrapRefusesExistingBusiness. PostgreSQL cases are NOT_RUN locally.
Impact: strict insert returns ErrConflict instead of overwriting. Account CLI opens an existing database without migrating. --dsn and --password still work and warn. capabilities --json does not touch the database.
Refs: docs/svc-deploy/u7-account-tx-audit.md
Co-authored-by: Cursor <cursoragent@cursor.com>