docs(audit): fix stale milestone labels + checkpoint + config — v1.29 complete, v1.30 scoped

Audit fixes:
- PROJECT.md: v1.28 + v1.29 subheaders 'Feature milestone — active' → 'complete'
- REQUIREMENTS.md: same fix (v1.28 + v1.29)
- PROJECT.md: v1.29 header '(active, milestone branch...)' → '(complete, tag v1.28.6, merged to main 2026-08-20)'
- REQUIREMENTS.md: same header fix
- config.json: active_milestone v1.29 → v1.30 (v1.29 complete, next milestone scoped)
- CHECKPOINT.json: cleared v1.29 complete state, set v1.30 phase 0 specify (per run.md clear-checkpoint)

---ci---
project: acdl
phase: 0
milestone: v1.30
status: specify
audit: fixes-applied
---/ci---

.ciagent/config.json

@@ -13,7 +13,7 @@
   ],
   "active_project": "acdl",
   "active_projects": ["acdl", "nova-blockchain-exchange"],
-  "active_milestone": "v1.29",
+  "active_milestone": "v1.30",
   "autonomy": {
     "level": "full",
     "escalation_hooks": ["deploy", "delete_data", "merge_to_main"],