Add a persisted field

1. Add a new migration. Keep applied migrations unchanged. Define the default or backfill for existing rows before making the field required.
2. Update the resource’s query SQL, domain input, and repository mapping.
3. Update the OpenAPI input/output schemas, including bounds and optionality.
4. Run task generate, then map the generated types in the handler. Apply omitted-value defaults there; validation does not inject them into requests.
5. Test create, read, update, invalid values, explicit null, omitted defaults, and migration of existing rows.
6. Run go run ./cmd/dev check and task test:integration.

Migrations use increasing numeric versions. Renumber an unapplied migration if parallel branches chose the same version. Review rollback behavior before deployment, especially when it removes data.

A passing build does not prove persistence: write the field and read it back from the real test database.