新增仿真执行过程回放

结论：真实浏览器仿真页面新增 G-code 执行过程和刀具运动回放，支持 reset、step、play、finish，逐帧高亮 G-code 与 motion row，并渲染已执行刀路和移动 toolhead。

PROJECT_COMPLETION_TRACKER.md

@@ -40,7 +40,7 @@ The project is complete for the current scope when all of the following are true
 | --- | --- | --- |
 | LinuxCNC semantic boundary | Stable | JS/browser remains glue, staging, OPFS, WASM/browser boundary, docs, and tests only. |
 | Real browser simulation priority | Active first priority | Future batches should prioritize the real UI/browser CNC simulation page, with visible machine/session loading, G-code program state, LinuxCNC-backed interpreter execution, machine readiness/status panels, toolpath/preview rendering from LinuxCNC-produced output or validated runtime events, and browser smoke coverage. First entry point: `wasm-port/runtime/ui/simulation/index.html`; gate: `wasm-port/tests/browser/verify_real_simulation_browser.sh`. See `wasm-port/docs/real-browser-simulation-priority.md`. |
-| Real browser simulation page | MVP active | `runtime/ui/simulation/index.html` loads in Chromium, exposes a selector for multiple LinuxCNC-backed test programs, runs them through interpreter WASM, renders program lines, final axis readout, canonical event table, raw canonical output, and SVG toolpath preview. Current program set covers square contour, Z pocket contour, incremental loop, G2/G3 arcs, and G81 drilling. |
+| Real browser simulation page | MVP active | `runtime/ui/simulation/index.html` loads in Chromium, exposes a selector for multiple LinuxCNC-backed test programs, runs them through interpreter WASM, and now includes reset/step/play/finish playback over LinuxCNC canonical motion events. It highlights active G-code and motion rows, updates live axis readout, moves the toolhead, and grows the executed SVG toolpath. Current program set covers square contour, Z pocket contour, incremental loop, G2/G3 arcs, and G81 drilling. |
 | Vendor/source guard | Stable | `verify_vendor_sync.sh` and standalone semantic guard are required every batch. |
 | Interpreter WASM smoke | Stable | `interp_wasm_node_smoke=ok`. |
 | Sim config inventory | Stable with skips | `executed=28`, `passed=28`, `skipped=131`, `unexpected_fail=0`; `docs/sim-configs-coverage-handoff.md` records the release-gate baseline. |
@@ -85,6 +85,9 @@ Current first priority:
 - The page now includes selectable test programs for square contour, Z pocket
   contour, incremental loop, G2/G3 arcs, and G81 drilling, with browser smoke
   coverage for each program.
+- Playback controls now expose reset/step/play/finish over LinuxCNC canonical
+  motion events, with active G-code line highlighting, active motion row
+  highlighting, live axis readout, moving toolhead, and executed-path rendering.
 - The page must be visible and operator-oriented, not another release dashboard.
 - It should use OPFS/session persistence, staged G-code, and existing
   LinuxCNC-backed WASM SDK execution.