docs(physics): C1 satisfied by the existing publication mechanism

The C1 body-writer research found the atomic controller/body transaction
already built and tested: RuntimeLocalPlayerPhysicsPublicationState plus
the dormant local-activation family implement the sanctioned
off-canonical-prepare + validated-atomic-commit shape end-to-end, with
zero production callers. The committed writer map records the six
canonical body writers, the two host escape hatches (the public
Controller setter both hosts write directly; App's object-clock facade
bypasses), the headless prepared-collision fragility, and both hosts'
construction divergences. C1 therefore collapses into C3's route-1 flip
— the remaining work is production wiring, not mechanism design — and
C2 (the placement allocation budget) becomes the next slice.

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

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

@@ -74,12 +74,24 @@ same commit) → docs/handoff commit. No workarounds; no fused slices.
   deferral; refine at C3/C4 if the connected gates show it matters);
   (c) any future host exposure of `TrySetAutonomyLevel` must carry retail's
   `SendAutonomyLevelEvent` (699550).
-- **C1 — atomic controller/body publication (prerequisite C).** One
-  Runtime-owned transaction publishing the exact same canonical body to
-  graphical and no-window controllers, prepared off-canonical, committed
-  atomically, respected by every body writer/binding/clock-epoch/teardown
-  path. The rejected snapshot-lease design stays rejected. Adversarial-gate
-  heavy (the campaign handoff's full list).
+- **C1 — atomic controller/body publication — SATISFIED BY EXISTING
+  MECHANISM (research finding 2026-08-02, plan amended same session).**
+  `RuntimeLocalPlayerPhysicsPublicationState` (1,033 lines) plus the
+  ~15-method dormant local-activation family on `RuntimeSetPositionState`
+  already implement the full sanctioned option-2 transaction:
+  off-canonical preparation against a scratch quantum clock and a sealed
+  candidate controller, one validated atomic Commit, and a staged
+  Evaluate/Commit/FinalizeActivation chain re-validated against
+  PhysicsOwnershipEpoch/ObjectClockEpoch/ControllerOwnershipEpoch/session
+  identity at every entry — with zero production callers. See
+  [`2026-08-02-canonical-body-writer-map.md`](../research/2026-08-02-canonical-body-writer-map.md)
+  (6 canonical body writers; the two host escape hatches; both hosts'
+  divergences). The remaining work — routing both hosts' local-player
+  construction through the publication lifecycle, sealing the public
+  `RuntimeLocalPlayerMovementState.Controller` setter, retiring App's
+  direct object-clock bypasses, and containing headless's uncaught
+  prepared-collision `InvalidDataException` — IS the C3 route-1 flip and
+  moves there. No separate C1 commit.
 - **C2 — placement allocation budget.** Pool or eliminate the operation/
   projection envelope allocations on the accepted placement path (root
   cause, not a raised cap), or obtain explicit user approval for a measured