feat(frontend): perbagus voice & audio playback UX

- Recordings: custom RecordingAudioPlayer (play/pause, buffering spinner,
  click-to-seek, time label, eq bars, single-playback antar kartu) +
  highlight kartu now-playing
- Media: thumbnail di disc hero + queue row, equalizer saat playing,
  badge 'up next', label Paused vs Now playing
- MiniPlayer global di AppFrame (fixed bottom-right, hidden on /media)
  menggantikan use-media-player.tsx dead provider (dihapus)
- Voice: mic level meter live (AnalyserNode RMS) + slider mic/listen volume

services/frontend/src/components/shell/ambient-app.tsx

@@ -1,3 +1,4 @@
+import { MiniPlayer } from "@/components/media/mini-player";
 import { MobileNav } from "./mobile-nav";
 import { NavRail } from "./nav-rail";
 import { TopBar } from "./topbar";
@@ -9,7 +10,8 @@ import { TopBar } from "./topbar";
  *
  * < md the side rail collapses (hidden) and a bottom tab bar (MobileNav)
  * takes over navigation; the content region gains bottom padding so the last
- * panel never hides behind the dock.
+ * panel never hides behind the dock. A persistent MiniPlayer floats at the
+ * bottom-right whenever a media track is loaded outside /media.
  */
 export function AppFrame({ children }: { children: React.ReactNode }) {
   return (
@@ -22,6 +24,7 @@ export function AppFrame({ children }: { children: React.ReactNode }) {
         </main>
       </div>
       <MobileNav />
+      <MiniPlayer />
     </div>
   );
 }