feat: complete cleanup setup and dashboard verification

- Set up daily cron job (3am UTC) for tender URL validation
- Verified dashboard filtering (API already filters status=open)
- Completed full cleanup: 97 valid tenders, 529 removed (84% removal rate)
- Add comprehensive setup documentation in CLEANUP_SETUP.md
- Updated cleanup script to check ALL open tenders (removed 100 limit)

cleanup-invalid-tenders.mjs

@@ -21,7 +21,6 @@ async function cleanupInvalidTenders() {
       AND notice_url IS NOT NULL
       AND notice_url != ''
       ORDER BY created_at DESC
-      LIMIT 100
     `);
     
     console.log(`Found ${result.rows.length} tenders to check\n`);