feat: SSE push for worklist updates — instant missed-call notifications

New worklist SSE stream replaces the 30s frontend poll. When the
missed-call webhook creates a Call record, it emits a worklist-updated
event via the supervisor's worklistSubject. All connected agents
receive the event immediately.

- supervisor.service.ts: worklistSubject + emitWorklistUpdate()
- supervisor.controller.ts: @Sse('worklist/stream') broadcast endpoint
- missed-call-webhook.controller.ts: emits after createCall() with
  callerPhone + callerName for toast notification
- worklist.module.ts: imports SupervisorModule (forwardRef)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/supervisor/supervisor.controller.ts

@@ -52,4 +52,18 @@ export class SupervisorController {
             } as MessageEvent)),
         );
     }
+
+    // Worklist SSE — broadcast to all connected agents. When a missed
+    // call is created by the webhook, this fires immediately so agents
+    // don't wait for the 30s worklist poll. The payload includes the
+    // caller's phone + name for a toast notification.
+    @Sse('worklist/stream')
+    streamWorklistUpdates(): Observable<MessageEvent> {
+        this.logger.log('[SSE] Worklist stream opened');
+        return this.supervisor.worklistSubject.pipe(
+            map(event => ({
+                data: JSON.stringify(event),
+            } as MessageEvent)),
+        );
+    }
 }