Classify missing open audit findings

[stainlu]

Summary

• keep missingOpen as the total audit count while adding classified missing-open buckets
• classify missing open records as eligible, maintainer-authored, protected-label, or recently-created queue lag
• make strict audit mode fail on actionable missing-eligible drift instead of expected protected/maintainer/recent misses
• include author association and timestamps in live missing/open-archived audit findings

Verification

• npm run check
• npm run audit -- --max-pages 250 --sample-limit 3 --output /tmp/clawsweeper-classified-audit.json

Live audit signal

The classified audit completed against openclaw/openclaw with 9,334 live open items across 94 pages. It reported missingOpen: 169 but missingEligibleOpen: 0; the missing records were missingMaintainerOpen: 41, missingProtectedOpen: 34, and missingRecentOpen: 94. That keeps the total visibility while removing false strict failures from expected queue lag and excluded items.