feat(voice): WhatsApp Cloud Calling — UI [6] (#14346)

## Summary

Frontend for WhatsApp Cloud Calling: header / contact-panel call
buttons, ringing widget, accept/reject/hangup, mute, in-bubble audio
player + transcript, recording-on-hangup upload, mid-call reload
warning. WebRTC is browser-direct to Meta — no media server bridge.

## Closes
- https://linear.app/chatwoot/issue/PLA-150

## How to test

Requires backend support — the controller, services, model changes, and
routes ship in **#14334** (`feature/pla-150`). Merge / deploy that first
(or simultaneously); the FE alone won't function without those
endpoints.

Then on staging, for a WhatsApp Cloud + embedded-signup inbox with the
new \`Configuration → Enable voice calling\` toggle ON and webhook
registered:

1. **Outbound** — open a conversation, click the phone icon in the
conversation header (or contact panel), grant mic, your phone rings,
answer, audio both ways, hang up. Recording + transcript land in the
bubble within ~10s.
2. **Inbound** — call the business number from your phone. The
FloatingCallWidget appears bottom-right with caller name. Click accept,
audio both ways, hang up. Recording + transcript appear.
3. **Mute** — during an active WhatsApp call, click the mic icon next to
hangup. Speech stops reaching Meta until you click again.
4. **Mid-call reload guard** — try `Cmd-R` during an active call;
browser shows a confirm prompt.

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: iamsivin <iamsivin@gmail.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>

app/javascript/dashboard/components-next/message/chips/Audio.vue

@@ -41,8 +41,33 @@ const playbackSpeed = ref(1);
 
 const { uid } = getCurrentInstance();
 
+// MediaRecorder-produced WebM/Opus blobs lack a Duration header → <audio>.duration
+// resolves to Infinity until we seek past the end, which forces the engine to
+// scan the file and compute the real length. Safe no-op for files with a real
+// duration already (mp3/m4a/etc).
+const resolveStreamingDuration = () => {
+  const el = audioPlayer.value;
+  if (!el) return;
+  const onTimeUpdate = () => {
+    el.removeEventListener('timeupdate', onTimeUpdate);
+    el.currentTime = 0;
+    duration.value = el.duration;
+  };
+  el.addEventListener('timeupdate', onTimeUpdate);
+  try {
+    el.currentTime = Number.MAX_SAFE_INTEGER;
+  } catch {
+    el.removeEventListener('timeupdate', onTimeUpdate);
+  }
+};
+
 const onLoadedMetadata = () => {
-  duration.value = audioPlayer.value?.duration;
+  const d = audioPlayer.value?.duration;
+  if (!Number.isFinite(d)) {
+    resolveStreamingDuration();
+    return;
+  }
+  duration.value = d;
 };
 
 const playbackSpeedLabel = computed(() => {
@@ -53,7 +78,8 @@ const playbackSpeedLabel = computed(() => {
 // When the onLoadMetadata is called, so we need to set the duration
 // value when the component is mounted
 onMounted(() => {
-  duration.value = audioPlayer.value?.duration;
+  const d = audioPlayer.value?.duration;
+  if (Number.isFinite(d)) duration.value = d;
   audioPlayer.value.playbackRate = playbackSpeed.value;
 });