docs(physics): record cutover slice C3a completion

C3a landed at 960373df with dual review PASS. The plan records the
conductor's five-stage sequence (verified step-for-step against retail's
entry order, with the mover-shapes-first correction the tested
preconditions forced), the convergence/wiring closures, and the two
carried findings C3c must honor. Next: C3b remote body construction at
Create, whose float-gate oracle is committed at 874d94bf.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs/plans/2026-08-02-placement-cutover.md

@@ -136,9 +136,21 @@ same commit) → docs/handoff commit. No workarounds; no fused slices.
   not invention).
   Sub-slices, each with the standing contract/dual-review/gate
   discipline:
-  - **C3a — Runtime first-entry sequencing (dormant):** the resumable
+  - **C3a — Runtime first-entry sequencing — COMPLETE at `960373df`
-    local-player entry transaction binding residence → publication
+    (2026-08-02, dual reviews PASS).** `RuntimeLocalPlayerFirstEntryState`:
-    body-attach → mover submit → receipt → Execute, test-driven.
+    five stages (mover-prep → publication Prepare/Commit → activation →
+    acknowledgement → Execute) in retail's own order — mover shapes
+    BEFORE placement, matching makeObject/set_description preceding
+    enter_world; the original contract prose had it backwards and the
+    tested preconditions forced the faithful order. Acknowledge-stage
+    authority discrimination, automatic convergence through the (now
+    multicast, snapshot-iterated) retirement fan-out, ownership-ledger
+    fold, transactional late-bind Publication seam. Dormant: C3c's first
+    act is the GameRuntime binding + production Advance drive.
+    **Carried findings for C3c:** the controller is live from the
+    activation commit onward (abandonment leaves it to ordinary entity
+    teardown — retail has no entry-flow rollback); EvaluateActivation's
+    post-commit DeferredCell overload is encapsulated behind Advance.
   - **C3b — remote body construction at Create (dormant):**
     retail-anchored body construction from the wire PhysicsSpawnData per
     `set_description` order for residence-route remote/creature Creates.