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/widgets/ChannelItem.vue

@@ -56,6 +56,14 @@ const isActive = computed(() => {
     return props.enabledFeatures.channel_voice;
   }
 
+  if (key === 'whatsapp_call') {
+    return (
+      props.enabledFeatures.channel_voice &&
+      !!window.chatwootConfig?.whatsappAppId &&
+      window.chatwootConfig.whatsappAppId !== 'none'
+    );
+  }
+
   return [
     'website',
     'twilio',
@@ -78,7 +86,14 @@ const isComingSoon = computed(() => {
 });
 
 const isBeta = computed(() => {
-  return ['tiktok', 'voice'].includes(props.channel.key);
+  return ['tiktok', 'voice', 'whatsapp_call'].includes(props.channel.key);
+});
+
+const hasVoiceBadge = computed(() => {
+  return (
+    ['voice', 'whatsapp_call'].includes(props.channel.key) &&
+    !!props.enabledFeatures.channel_voice
+  );
 });
 
 const onItemClick = () => {
@@ -95,6 +110,7 @@ const onItemClick = () => {
     :icon="channel.icon"
     :is-coming-soon="isComingSoon"
     :is-beta="isBeta"
+    :has-voice-badge="hasVoiceBadge"
     :disabled="!isActive"
     @click="onItemClick"
   />