chore(glass): scrub dev-process/hostname refs from tracked comments

Code review (public-repo rule): the GlassTuner + index.css/App.tsx comments named
the prod hostname and dev-process jargon (UAT/HMR/dev ports/epic), which ship in
the public bundle. Genericised the comments — no behaviour change.

frontend/src/App.tsx

@@ -912,8 +912,7 @@ export default function App() {
       <ErrorDialog />
       {/* Re-binds to the active page's scroll container on navigation (page or channel change). */}
       <BackToTop dep={channelView ? `chan:${channelView.id}` : page} />
-      {/* DEV-ONLY live appearance tuner (localhost-gated; self-returns null on prod). Delete when
-          the glass-consistency epic bakes the final values into index.css. */}
+      {/* Local-only live appearance tuner (renders only on localhost; null everywhere else). */}
       <GlassTuner />
     </div>
   );