Reset Production Submissions

This is a destructive production operation. Use the connection procedure and firewall cleanup rules from query-prod-db.

1. Resolve the GitHub username through users; do not use remembered IDs.
2. Resolve any requested requirement slug to its UUID from the current curriculum artifact.
3. Preview matching rows from verification_attempts, including id, requirement_uuid, outcome, and timestamps. Scope by user_id and, unless resetting everything was explicit, requirement_uuid.
4. Show the exact count and scope, then obtain explicit user confirmation.
5. Delete only the previewed scope in one transaction using the same predicates. Use RETURNING id and verify the remaining count before commit.
6. Re-query after commit and report the deleted and remaining counts.

Progress is derived from verification_attempts; no counter requires updating. Do not use the retired submissions or verification_jobs tables. Do not broaden a requirement-scoped reset to all attempts. If the schema, username, or slug cannot be resolved unambiguously, stop without deleting.