docs(P00): clarify + research + plan — D-247 invariants locked

---ci---
project: acdl
phase: 0
milestone: v1.31
status: plan
---/ci---

.ciagent/CHECKPOINT.json

@@ -1,10 +1,10 @@
 {
   "phase": 0,
-  "stage": "specify",
+  "stage": "plan",
   "milestone": "v1.31",
   "phase_role": "pre_execution",
   "attempts": 0,
-  "updated_at": "2026-08-20T16:10:00Z",
+  "updated_at": "2026-08-20T16:18:00Z",
   "project": "acdl",
   "projects": ["acdl", "nova-blockchain-exchange"],
   "active_milestone": "v1.31",
@@ -24,5 +24,5 @@
     "releases_created": true,
     "release_ids": [811,812,813,814,818]
   },
-  "notes": "v1.31 SPECIFY. Refinement-only polish of v1.30 leadership deck (REQ-373.1..4, D-247 invariants). Tags run on v1.30.x line. No new features/slides/diagrams/theme tokens."
+  "notes": "v1.31 P0 complete (specify+clarify+research+plan). D-247 locked: refinement-only, theme-preserving invariants. Plan = single vertical slice P1: rewrite visible prose + improve layout in nova-leadership-deck-marp.md, re-render PPTX, smoke test must pass."
 }