# DATA-01 durable-invariant reproduction

This deterministic fixture contrasts a check-then-insert race with a shared
uniqueness boundary. It also models terminal key release, owner checks,
migration refusal, explicit canonical resolution, history preservation, and
the prohibition on new legacy exemptions.

Run:

```sh
./run.sh
```

It does not start a database, run concurrent processes, copy private code, or
verify a particular engine, isolation level, trigger, migration, or production
outcome. All records and identifiers are synthetic.