Feat/issue 37 cold storage

[AlAfiz]

Summary

Resolves Issue #37: [Database] Cold Storage for Completed Vaults.

As the protocol grows, active database tables will accumulate 100% claimed and completed vaults, which can eventually degrade query performance for active vaults. This PR introduces a cold storage archival system. It safely moves fully completed vaults (where claimable balance is 0 and the vesting end time has passed) into a dedicated archived_vaults table via a weekly scheduled job.

Acceptance Criteria Met

• Create an archived_vaults table.
• Run a weekly cron job to move vaults where claimable_balance == 0 and end_time has passed to the archive table.

Changes Made

• Created vaultArchivalJob.js:
  • Initializes the archived_vaults table on application boot.
  • Registers a node-cron job scheduled to run every Sunday at 02:00 AM (0 2 * * 0).
  • Identifies vaults with a claimable_balance of <= 0 and an expired end_time.
  • Securely copies the full vault payload (as JSON) into the archived_vaults table inside a database transaction.
  • Safely deletes the archived vault and its direct dependencies (SubSchedule, Notification) from the active tables to free up indexing space.
• Updated index.js:
  • Hooked the initialization of the VaultArchivalJob into the main application startup sequence.

How to Test

1. Pull down the branch and start the backend (npm run dev or docker-compose up).
2. Verify in your database client (e.g., pgAdmin, psql) that the archived_vaults table has been automatically created.
3. Optional for testing: Temporarily change the cron expression in vaultArchivalJob.js from '0 2 * * 0' to '* * * * *' (every minute) and set an active vault's end date to the past with a 0 balance to watch it get automatically archived in real-time.

Labels

• database
• optimization

Fixes #37