phase: 03_simulation_movement_and_interaction

**Final verification pass — phase 03 `simulation_movement_and_interaction` (all 5 task files already in `complete/`)**

- Verified all phase-03 deliverables exist and work: `sim/` kernel (`step`, `state_build`, `rng`, `movement`, `collision`, `interact`, `carry`, `replay`), replay fixtures + 3 committed goldens, `docs/SIMULATION.md`.
- `bash .agents/validate.sh` → **passed**: ruff `All checks passed!`, pyright `0 errors`, `undercooked-levels validate` green, full `pytest` **1033 passed** (coverage **99.71%** ≥ 90% floor), slow sim stage green, repo-hygiene clean.
- Perf smoke (4 players, 2 000 ticks): mean **0.049 ms/tick, 20 423 ticks/s** — ≥ 10 000 ticks/s criterion met (test lives in `test_perf_smoke.py`, which the gate's slow stage runs; the overview names it `test_replay.py`).
- Completion criteria: import `undercooked.sim.step.step` ✅ · `tests/sim` green incl. determinism + goldens ✅ · perf ✅ · constant-change-fails-by-design ✅ (committed-hash equality + mutation test naming first bad tick/field; goldens never rewritten by tests) · `docs/SIMULATION.md` ✅ (constants, 8-step order, purity/determinism, re-bless) · full suite + coverage ✅ · app launches: `/healthz` 200, `/` 200, `/api/levels` serves content ✅ · replay CLI `check walk_solo.json` exit 0 ✅ · no regression in phases 01/02 (their suites green) ✅.
- Documentation: README.md — fixed one stale inconsistency (Status opening listed only 01/02 complete with 03 pending; now lists 01–03 complete, next pending `04_kitchen_pipeline_and_scoring`); all other README claims (CLI flags, config table, shell text, replay CLI exit codes) verified against code. AGENTS.md — verified consistent with the project as it stands, no changes needed.
- No deviations. Next pending phase: **`04_kitchen_pipeline_and_scoring`**.

tests/unit/test_docs_index.py

@@ -210,6 +210,7 @@ def test_the_docs_on_disk_are_the_shipped_documents() -> None:
         "docs/DESIGN.md",
         "docs/DEPLOYMENT.md",
         "docs/LEVELS.md",
+        "docs/SIMULATION.md",
         "docs/TESTING.md",
     }