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。

wasm-port/README.md

@@ -19,7 +19,10 @@ G-code, tool, parameter, kinematics, remap, or planner semantics.
 The first real simulation entry point is `runtime/ui/simulation/index.html`,
 validated by `tests/browser/verify_real_simulation_browser.sh`. It now exposes
 multiple LinuxCNC-backed test programs from the page selector: square contour,
-Z pocket contour, incremental loop, G2/G3 arc path, and G81 drill pattern.
+Z pocket contour, incremental loop, G2/G3 arc path, and G81 drill pattern. The
+page also includes playback controls that step or play through LinuxCNC
+canonical motion events, highlighting the active G-code line and moving the
+toolhead over the executed toolpath.
 
 The project release gate for the current scope is: