Delete a statement and its movements (child-first).

This is what makes the file-hash idempotency safe: without a way to remove a statement, a file imported by mistake — or under the wrong account — could never be re-imported.

The gate is conditional rather than a blanket admin dependency. A statement with no invoice links is fully recoverable by re-importing the file, so anyone who may import may also delete one — the previous admin-only rule left ordinary users stuck with their own mistake. A statement WITH links is bulk-destructive (deleting it frees invoices that were matched), so it needs a company admin who passed force after being shown the affected invoices.