docs(init): validate v1.9 specification

---ci---
project: acdl
phase: 0
milestone: v1.9
status: specify
---/ci---

v1.9 scope (user-directed, 2026-07-23):
- Design doc refresh (hitl_matrix_design.md + audit_ledger_design.md)
- Contract interpolation (${env.<field>} + ${contract.<field>})
- Per-environment CI jobs (no environment field editing for promotion)
- Stub implementation (SoD, HITL gates, attestation matrix, Wiz, Kyverno)
- P1-1 adapter parameterization remediation

Requirements REQ-100..REQ-111 added to REQUIREMENTS.md.
PROJECT.md v1.9 objective + phase table (39-43) appended.
config.json milestone bumped to v1.9 (active).

.ciagent/config.json

@@ -4,8 +4,8 @@
     {
       "slug": "acdl",
       "name": "Agentic Cloud Delivery Platform",
-      "milestone": "v1.8",
-      "status": "complete"
+      "milestone": "v1.9",
+      "status": "active"
     }
   ],
   "active_project": "acdl",