docs(milestone): complete v1.19 — Nova 2nd-Release Sync

NFR-only chore milestone complete. P1 (nova-sync-script, v1.18.0) + P2
(final-review-ship, v1.18.1 = milestone release). REQ-229 satisfied.
Review clean, audit clean, 5 decisions locked (D-143..D-147).

---ci---
project: acdl
phase: 2
milestone: v1.19
status: complete
phase_role: final
requirements:
  covered: [REQ-229]
  partial: []
---/ci---

.ciagent/CHECKPOINT.json

@@ -1,13 +1,13 @@
 {
-  "phase": 1,
+  "phase": 2,
   "stage": "complete",
   "milestone": "v1.19",
-  "phase_role": "execution",
+  "phase_role": "final",
   "attempts": 0,
-  "updated_at": "2026-08-06T20:00:00Z",
-  "milestone_complete": false,
-  "tag": "v1.18.0",
-  "release_id": 530,
+  "updated_at": "2026-08-06T20:30:00Z",
+  "milestone_complete": true,
+  "tag": "v1.18.1",
+  "release_id": 531,
   "requirements": ["REQ-229"],
-  "notes": "v1.19 P1 SHIP complete: tag v1.18.0 (first patch on v1.18.x line), Gitea release id 530 created. 4-layer verify PASS. Next: P2 final-review-ship (review + audit + milestone complete)."
+  "notes": "v1.19 milestone complete. NFR-only chore milestone: 1 execution phase (P1 nova-sync-script, tag v1.18.0) + 1 final phase (P2 review+audit+ship, tag v1.18.1 = milestone release). scripts/sync_to_nova.sh replaces sync_to_gl.sh as manual-only 2nd-release pipeline ~/acdl -> ~/nova (GitLab jonathanchery/nova, separate repo/history, consumer/platform-team audience). Consumer subset rsync, 13 fixed-order domain commits via positional -m, conventional-commit validation. 8 new tests pass. Review clean (no P0). Audit clean (4/4 ci blocks, reconstruction OK, no secrets, sync_to_gl.sh removed). 5 decisions locked (D-143..D-147). Next milestone starts fresh."
 }