支持真实G代码程序执行

结论：AXIS 风格浏览器仿真页面新增 Open Program、runProgramText 和 loadProgramFile，支持用户提供的 G-code 文本/文件通过 LinuxCNC WASM 执行并参与回放。

wasm-port/runtime/ui/simulation/simulation-app.js

@@ -306,9 +306,11 @@ export function renderSimulationPlaybackFrame(documentRef, state, index = state.
 export function renderSimulationState(documentRef, state) {
   documentRef.body.dataset.simulationReady = state.summary.ready ? "true" : "false";
   documentRef.body.dataset.simulationProgramId = state.program?.id ?? "custom";
+  documentRef.body.dataset.simulationProgramSource = state.program?.source ?? "custom";
   setText(documentRef, "[data-simulation-status]", state.summary.ready ? "ready" : "blocked");
   setText(documentRef, "[data-runtime-status]", state.summary.rows[0].value);
   setText(documentRef, "[data-selected-program]", state.program?.label ?? "Custom program");
+  setText(documentRef, "[data-program-source]", state.program?.sourceLabel ?? "Custom G-code text");
   setText(documentRef, "[data-canonical-output]", state.resultText);
   renderProgramSelector(documentRef, state.program?.id ?? "custom");
   renderRows(documentRef, state.summary.rows);
@@ -330,7 +332,15 @@ export async function runRealBrowserSimulation({
   const state = {
     apiName: "real-browser-simulation-state",
     stateVersion: 1,
-    program: program ? { ...program, text: undefined } : null,
+    program: program
+      ? { ...program, source: "builtin", sourceLabel: "Built-in test program", text: undefined }
+      : {
+          id: "custom",
+          label: "Custom G-code program",
+          category: "Custom",
+          source: "custom",
+          sourceLabel: "Custom G-code text",
+        },
     programText: resolvedProgramText,
     resultText,
     motion,