Quarantine three test files consistently failing on the non-blocking
full-suite CI on main, per the AGENTS.md deletion-ratchet policy:
- engine self-healing-fn-5488-fast-path-regressions.test.ts (shard 1)
- engine in-review-merge-stall-deadlock-recovery.test.ts (shard 2)
- dashboard DevServerView.mobile.test.tsx (shard 4)
Each has a matching entry in scripts/lib/test-quarantine.json with
the failing CI run link and quarantinedAt date. Tests will be deleted
after 14 days unless rescued with a root-cause fix.