body: moving-step failure fails the Simulation; S1 acceptance tests

A failed MovingCircle.advance now calls the owner hook, so the Simulation
is marked failed (Jet lifecycle) and refuses run/step/sync until close().
Adds host tests for set_body routing on real objects, initialize band and
mode rejections before mutation, exclusion from static link packing, and
the Simulation failure lifecycle. Contract status line updated for S1.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/moving_bodies.md

@@ -1,6 +1,11 @@
 # Moving circles on the uniform dense grid — S0 DRAFT contract
 
-Status: **DRAFT for review, not frozen.** No implementation exists. Base: main
+Status: **DRAFT, not frozen** for the force RHS, kernels and physical
+acceptance. Host-only S1 (state, validation, guards; no kernels) is on branch
+`claude/moving-bodies-s1`; positive-step runs with a moving body are rejected
+until S2. When S2 lifts that guard, `run(n > 1)` with a pending target must
+raise `ValueError` before mutation (4a), and `run(0)` must not upload a motion
+record or consume the pending target. Base: main
 `b2034f87e03656c5f67ab88562a70d6c338b9918`. Scope approved by Frank (via TRON,
 thread C0C78UFKGRM/1793335557.460509): uniform-grid prescribed translation and
 single-cylinder free transverse VIV. Out of scope: refinement/blocked path,