fix(voice): thread callSid through agent leg + conference API clients

Required by the stricter server-side call_sid requirements from the
previous commit. Without this, agents would fail to join or leave calls
because the client side still sent only conversation_id.

- TwilioVoiceClient.joinClientCall now forwards callSid as a Device.connect
  param, which becomes params[:call_sid] on the TwiML webhook.
- VoiceAPI.leaveConference takes callSid and passes it as a query param
  so the DELETE /conference endpoint can resolve the exact call.
- useCallSession and FloatingCallWidget pass callSid through.

app/javascript/dashboard/api/channel/voice/twilioVoiceClient.js

@@ -68,7 +68,7 @@ class TwilioVoiceClient extends EventTarget {
     this.inboxId = null;
   }
 
-  async joinClientCall({ to, conversationId }) {
+  async joinClientCall({ to, conversationId, callSid }) {
     if (!this.device || !this.initialized || !to) return null;
     if (this.activeConnection) return this.activeConnection;
 
@@ -76,6 +76,7 @@ class TwilioVoiceClient extends EventTarget {
       To: to,
       is_agent: 'true',
       conversation_id: conversationId,
+      call_sid: callSid,
     };
 
     const connection = await this.device.connect({ params });

app/javascript/dashboard/api/channel/voice/voiceAPIClient.js

@@ -12,10 +12,10 @@ class VoiceAPI extends ApiClient {
     return ContactsAPI.initiateCall(contactId, inboxId).then(r => r.data);
   }
 
-  leaveConference(inboxId, conversationId) {
+  leaveConference({ inboxId, conversationId, callSid }) {
     return axios
       .delete(`${this.baseUrl()}/inboxes/${inboxId}/conference`, {
-        params: { conversation_id: conversationId },
+        params: { conversation_id: conversationId, call_sid: callSid },
       })
       .then(r => r.data);
   }

app/javascript/dashboard/components/widgets/FloatingCallWidget.vue

@@ -44,6 +44,7 @@ const handleEndCall = async () => {
   await endCallSession({
     conversationId: call.conversationId,
     inboxId,
+    callSid: call.callSid,
   });
 };
 

app/javascript/dashboard/composables/useCallSession.js

@@ -42,8 +42,8 @@ export function useCallSession() {
     );
   });
 
-  const endCall = async ({ conversationId, inboxId }) => {
-    await VoiceAPI.leaveConference(inboxId, conversationId);
+  const endCall = async ({ conversationId, inboxId, callSid }) => {
+    await VoiceAPI.leaveConference({ inboxId, conversationId, callSid });
     TwilioVoiceClient.endClientCall();
     durationTimer.stop();
     callsStore.clearActiveCall();
@@ -66,6 +66,7 @@ export function useCallSession() {
       await TwilioVoiceClient.joinClientCall({
         to: joinResponse?.conference_sid,
         conversationId,
+        callSid,
       });
 
       callsStore.setCallActive(callSid);