feat(fe): recordings — visible playing/loading/paused states

- recording-card: kartu aktif di-highlight (ring primary + glow pulse),
  badge 'Now Playing'/'Loading'/'Paused', tombol play berubah jadi Pause
  saat playing dan spinner saat loading, waveform equalizer beranimasi
  (animate-eq, delay per bar) saat playing / pulse saat loading.
- recording-player: jadi now-playing panel — tombol play/pause + spinner
  loading, progress bar + waktu (current/duration), status 'loading…',
  audio element pindah ke sini + event onPlay/onPause/onWaiting/onCanPlay/
  onPlaying/onError naik ke page.
- recordings/page: state isPlaying/isLoadingAudio + audioRef, togglePlay
  (klik card lain = ganti track, klik card sama = pause/resume).
- globals.css: keyframes eq-bounce + card-glow.

Verified: FE tsc0, next build 10/10 static pages.

services/frontend/src/app/globals.css

@@ -167,6 +167,38 @@
   animation: shimmer 1.5s infinite;
 }
 
+/* Equalizer bars — bouncing heights for the "now playing" waveform */
+@keyframes eq-bounce {
+  0%,
+  100% {
+    transform: scaleY(0.25);
+  }
+  30% {
+    transform: scaleY(1);
+  }
+  60% {
+    transform: scaleY(0.5);
+  }
+}
+.animate-eq {
+  animation: eq-bounce 0.9s ease-in-out infinite;
+  transform-origin: bottom;
+}
+
+/* Soft pulsing glow for the active/loading card */
+@keyframes card-glow {
+  0%,
+  100% {
+    box-shadow: 0 0 0 0 oklch(0.62 0.17 215 / 0);
+  }
+  50% {
+    box-shadow: 0 0 22px 0 oklch(0.62 0.17 215 / 0.25);
+  }
+}
+.animate-card-glow {
+  animation: card-glow 1.8s ease-in-out infinite;
+}
+
 /* ── Utility classes ─────────────────────── */
 
 /* Gradient text */