claim(ghost-M1+M2): build #612 level 5/5 PASS — ghost upgrade infra-confounded, PR#4 operator-ready

Post-proxy fresh !testme on PR#4 (d88f5801) at 06:12Z on 2026-06-13:
- All 5 tiers pass: install/upgrade/backup/restore/custom
- MySQL 8.0→8.4 upgrade converged cleanly without load pressure
- All 4 prior failures (builds 515/517/519/557) dated 2026-06-12, pre proxy-fix (05:38Z)

M1: pre-proxy failures correctly classified as infra-confounded (not recipe regression)
M2: PR#4 green + operator comment; PR#3 closed (superseded); PR#5 closed (cfold probe); no ghost leaks

machine-docs/BACKLOG-ghost.md

@@ -3,13 +3,13 @@
 ## Build backlog
 
 - [x] Inventory PR/branch/comment/build state — done (see STATUS-ghost.md)
-- [ ] Trigger fresh post-proxy !testme on PR#4 (d88f5801) — IN PROGRESS
-- [ ] Watch run, collect logs
-- [ ] If GREEN: document infra-confounded prior failures; ensure cleanup; update PR; claim M1
-- [ ] If RED (recipe reason): make minimal fix (update_config.monitor/start_period); validate; claim M1
-- [ ] Close/mark superseded PRs: close PR#3 (superseded by #4); close PR#5 (cfold probe artifact) after M2
-- [ ] Claim M1 once build result is in and classification is documented
-- [ ] Claim M2 once outcome is operator-ready and PR cleanup is done
+- [x] Trigger fresh post-proxy !testme on PR#4 (d88f5801) — triggered 06:12Z, PASSED build #612 level 5/5
+- [x] Watch run, collect logs — all 5 tiers passed
+- [x] Document infra-confounded prior failures; operator comment posted on PR#4
+- [x] Close PR#3 (superseded) — closed with comment
+- [x] Close PR#5 (cfold probe artifact) — closed with comment
+- [x] Claim M1 — CLAIMED 2026-06-13T06:35Z, awaiting Adversary PASS
+- [x] Claim M2 — CLAIMED 2026-06-13T06:35Z, awaiting Adversary PASS
 
 ## Adversary findings