docs(P00): research findings — v1.28 CLI + identity layer (11 Qs, D-228 amended)

---ci---
project: acdl
phase: 0
milestone: v1.28
status: research
---/ci---

.ciagent/CHECKPOINT.json

@@ -1,10 +1,10 @@
 {
   "phase": 0,
-  "stage": "clarify",
+  "stage": "research",
   "milestone": "v1.28",
   "phase_role": "pre_execution",
   "attempts": 0,
-  "updated_at": "2026-08-19T20:10:00Z",
+  "updated_at": "2026-08-19T20:25:00Z",
   "project": "acdl",
   "projects": ["acdl", "nova-blockchain-exchange"],
   "active_milestone": "v1.28",
@@ -13,5 +13,6 @@
   "tag_line": "v1.27.x",
   "previous_milestone": {"milestone": "v1.27", "tag": "v1.26.3", "status": "complete"},
   "decisions": ["D-226", "D-227", "D-228", "D-229", "D-230", "D-231"],
-  "notes": "v1.28 CLARIFY. 6 open Qs + 5 grounding gaps resolved at full autonomy. D-226..D-231 authored (confidence >= 0.80). kj mapped to kyverno-json (D-227). Cognito-drop reframed as greenfield (G3). CAP-033..038, INV-12..17, REQ-323..353 allocated. Next: RESEARCH."
+  "personas": ["backend-engineer", "security-engineer", "cli-engineer", "lead-developer"],
+  "notes": "v1.28 RESEARCH complete. 11 questions answered via ci-researcher subagent. D-228 amended (fail-closed, not pure-Python fallback). kj-binary-in-Lambda-layer is highest risk (P2 spike). KMS = ECC_NIST_P256 / ES256 with DER->raw conversion. nova-pats = 4th DDB table. mode_resolver uses sys.stdin.isatty(). PERSONAS.md + ARCHITECTURE.md §12.10 authored. Next: PLAN."
 }