Run bootstrap after async SDK load

main.js

@@ -11,6 +11,14 @@ const transportModule = new URLSearchParams(location.search).get("transport") ==
     ? "./reachy-mini-cloud.js"
     : "./reachy-mini-local.js";
 const { ReachyMini, rpyToMatrix } = await import(transportModule);
+
+function onDomReady(callback) {
+    if (document.readyState === "loading") {
+        document.addEventListener("DOMContentLoaded", callback, { once: true });
+    } else {
+        callback();
+    }
+}
 
 // MediaPipe Tasks-Vision is a multi-megabyte ESM bundle. Importing it
 // at the top of the module would block DOMContentLoaded (and therefore
@@ -1333,7 +1341,7 @@ window.addEventListener("beforeunload", shutdown);
 // extraction always reads the un-flipped frame; the mapper flips
 // head_yaw at the output). Wired here so the CSS class applies
 // immediately on click, even before streaming.
-document.addEventListener("DOMContentLoaded", () => {
+onDomReady(() => {
     const t = $("toggleMirror");
     if (t) t.addEventListener("change", applyMirrorClass);
 
@@ -1417,4 +1425,4 @@ async function bootstrap() {
     }
 }
 
-document.addEventListener("DOMContentLoaded", bootstrap);
+onDomReady(bootstrap);