[FEATURE] Wipe events table script #421

Describe the solution you'd like
I would like a new administrative CLI script, likely triggered via npm run clean-db, that provides a safe and structured way to wipe or prune the events table. Other tables are out of scope.

Functional Requirements:

1. Safety First: The script must require an explicit confirmation (e.g., Type 'DELETE' to confirm) or a --force flag to prevent accidental data loss in production.
2. Flexible Purging Options:
   • --all: Perform a full wipe of the events data.
   • --older-than=[days]: Delete events based on the created_at timestamp.
   • --kinds=[1,7,4]: Target specific Nostr event kinds for removal.
3. PostgreSQL Optimizations:
   • For the --all flag, the script should use TRUNCATE TABLE events RESTART IDENTITY CASCADE; for near-instant execution and immediate disk space reclamation.
   • For selective deletes, the script should run VACUUM ANALYZE events; afterward to ensure the Postgres query planner is updated.
4. Dry Run: A --dry-run flag to output the count of rows that would be affected without executing the deletion.

Describe alternatives you've considered

• Manual SQL execution: Hard to script and maintain across different deployment environments.
• Dropping the Database: Overkill, as it requires re-running migrations and re-configuring permissions/extensions (like pgcrypto).

Additional context

Technical Implementation Details:

• Batching: If deleting millions of rows via --older-than, the script should ideally delete in batches to avoid bloating the WAL (Write-Ahead Log) or locking the table for an extended period. Optional.
• Referential Integrity: Ensure that related data in auxiliary tables (like tags or deletions) is handled correctly, leveraging PostgreSQL's CASCADE or explicit sub-queries.
• Environment Check: The script should check the NODE_ENV and provide an extra warning if it detects a production environment.

Expected Outcomes:

• A new clean-db utility script.
• The ability to quickly reset a relay's state during data-heavy testing.
• Updated README.md instructions for relay maintenance.