fix(voice): terminate ringing WhatsApp calls on page close

Browser-direct WebRTC has no rejoin path, so any call that outlives the
agent's tab becomes permanently orphaned on Meta's side. The existing
pagehide beacon only covered the active (accepted) call — extend it to
every ringing inbound too, so a hard refresh during ringing releases the
call instead of leaving Meta to time it out.

- useWhatsappCallSession: factor sendWhatsappCallBeacon(callId) out of
  the active-call wrapper so any caller can post terminate for any callId
  without going through the activeCallId / intentionallyClosing guard.
- useCallSession.handlePageHide: after the active-call beacon, iterate
  the calls store for any ringing WhatsApp call and beacon /terminate
  for each. terminate is the right endpoint because the backend records
  it as 'no_answer' when the call was still ringing — accurate UX shape.

app/javascript/dashboard/composables/useCallSession.js

@@ -6,6 +6,7 @@ import { useCallsStore } from 'dashboard/stores/calls';
 import {
   useWhatsappCallSession,
   sendWhatsappTerminateBeacon,
+  sendWhatsappCallBeacon,
   cleanupWhatsappSession,
 } from 'dashboard/composables/useWhatsappCallSession';
 import { handleVoiceCallCreated } from 'dashboard/helper/voice';
@@ -69,10 +70,15 @@ export function useCallSession() {
     });
   };
 
-  // pagehide fires after the user confirms the prompt. Let the WhatsApp session
-  // best-effort sendBeacon a terminate so the server doesn't keep the call open.
+  // pagehide fires after the user confirms the prompt. Beacon a terminate for
+  // every WhatsApp call in the store — active OR ringing — since browser-direct
+  // WebRTC has no rejoin path, so any call that survives the close becomes
+  // permanently orphaned on Meta's side.
   const handlePageHide = () => {
     sendWhatsappTerminateBeacon();
+    callsStore.calls
+      .filter(c => c.provider === 'whatsapp' && !c.isActive && c.callId)
+      .forEach(c => sendWhatsappCallBeacon(c.callId));
   };
 
   const handleTwilioDisconnected = () => callsStore.clearActiveCall();