fix(desktop): address code-review findings on the desktop wave

- fileEntries: a single unreadable file/dir in a dropped folder no longer aborts
  the whole traversal (try/catch per entry, skip failures) — was discarding ALL
  dropped files (incl. the flat-file path) + an unhandled rejection; also add
  .catch in both useFileDrop consumers.
- RoomInput: mirror a localStorage-restored draft into the draft atom so the
  P5-57 indicator reflects a persisted draft after a page reload, not only on
  same-session room re-entry.
- useTauriThumbbar: swallow toggleMicrophone()/hangup() rejections (parity with
  SMTC) — avoids an unhandled rejection when clicked mid-teardown.
- App/DesktopChrome: keep wrapper element types stable across the chrome toggle
  (display:contents when off) so flipping it no longer remounts RouterProvider.
- settings: normalizeComposerToolbarOrder also appends missing keys from the
  canonical key set (safety net if a new button is absent from the default order).

Gates: tsc/eslint/prettier clean, build OK, 559 tests.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/pages/App.tsx

@@ -100,11 +100,24 @@ function TauriEffects() {
 function DesktopChrome({ children }: { children: ReactNode }) {
   const customChrome = useAtomValue(customWindowChromeAtom);
   useTauriWindowChrome();
-  if (!(isTauri() && customChrome)) return <>{children}</>;
+  const useChrome = isTauri() && customChrome;
+  // Keep the wrapper element structure STABLE across the toggle so flipping the
+  // setting never changes the element type in `children`'s ancestry — otherwise
+  // React would unmount/remount the whole RouterProvider subtree (losing scroll,
+  // menus, unsaved composer state). When off, both wrappers use `display:contents`
+  // so they generate no box → zero layout impact (also the browser default path).
   return (
-    <div style={{ display: 'flex', flexDirection: 'column', height: '100vh' }}>
-      <TitleBar />
-      <div style={{ flexGrow: 1, minHeight: 0 }}>{children}</div>
+    <div
+      style={
+        useChrome
+          ? { display: 'flex', flexDirection: 'column', height: '100vh' }
+          : { display: 'contents' }
+      }
+    >
+      {useChrome && <TitleBar />}
+      <div style={useChrome ? { flexGrow: 1, minHeight: 0 } : { display: 'contents' }}>
+        {children}
+      </div>
     </div>
   );
 }