feat: real-time active call SSE — hold/unhold status for supervisor live monitor

- SupervisorService: added activeCallSubject (RxJS Subject), emits on all
  activeCalls Map mutations (Answered, Calling, Disconnect, Hold, Unhold)
- SupervisorController: new @Sse('active-calls/stream') endpoint
- OzonetelAgentController: callControl HOLD/UNHOLD updates activeCalls Map
  status via supervisor.updateCallStatus()

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

src/ozonetel/ozonetel-agent.controller.ts

@@ -382,6 +382,13 @@ export class OzonetelAgentController {
 
         try {
             const result = await this.ozonetelAgent.callControl(body);
+
+            if (body.action === 'HOLD') {
+                this.supervisor.updateCallStatus(body.ucid, 'on-hold');
+            } else if (body.action === 'UNHOLD') {
+                this.supervisor.updateCallStatus(body.ucid, 'active');
+            }
+
             return result;
         } catch (error: any) {
             const message = error.response?.data?.message ?? error.message ?? 'Call control failed';

src/supervisor/supervisor.controller.ts

@@ -13,6 +13,16 @@ export class SupervisorController {
         return this.supervisor.getActiveCalls();
     }
 
+    @Sse('active-calls/stream')
+    streamActiveCalls(): Observable<MessageEvent> {
+        this.logger.log('[SSE] Active calls stream opened');
+        return this.supervisor.activeCallSubject.pipe(
+            map(event => ({
+                data: JSON.stringify(event),
+            } as MessageEvent)),
+        );
+    }
+
     @Get('team-performance')
     async getTeamPerformance(@Query('date') date?: string) {
         const targetDate = date ?? new Date().toISOString().split('T')[0];

src/supervisor/supervisor.service.ts

@@ -36,6 +36,7 @@ export class SupervisorService implements OnModuleInit {
     private readonly agentStates = new Map<string, AgentStateEntry>();
     private readonly acwTimers = new Map<string, NodeJS.Timeout>();
     readonly agentStateSubject = new Subject<{ agentId: string; state: AgentOzonetelState | string; timestamp: string }>();
+    readonly activeCallSubject = new Subject<{ type: 'update' | 'remove'; call?: ActiveCall; ucid: string }>();
     // Worklist update stream — emitted when a missed call is created or
     // assigned. Frontend SSE listener triggers an immediate worklist
     // refresh so agents see new missed calls without waiting for the 30s poll.
@@ -95,10 +96,9 @@ export class SupervisorService implements OnModuleInit {
                 this.logger.warn(`Ignoring call event for offline agent ${agentId} (${ucid})`);
                 return;
             }
-            this.activeCalls.set(ucid, {
-                ucid, agentId, callerNumber,
-                callType, startTime: eventTime, status: 'active',
-            });
+            const call: ActiveCall = { ucid, agentId, callerNumber, callType, startTime: eventTime, status: 'active' };
+            this.activeCalls.set(ucid, call);
+            this.activeCallSubject.next({ type: 'update', call, ucid });
             this.logger.log(`Active call: ${agentId} ↔ ${callerNumber} (${ucid})`);
 
             // Persist CALL_START as AgentEvent on the "Answered" moment
@@ -130,6 +130,7 @@ export class SupervisorService implements OnModuleInit {
         } else if (action === 'Disconnect') {
             const wasActive = this.activeCalls.get(ucid);
             this.activeCalls.delete(ucid);
+            this.activeCallSubject.next({ type: 'remove', ucid });
             this.logger.log(`Call ended: ${ucid}`);
 
             // Persist CALL_END — pair against the start for duration.
@@ -294,6 +295,17 @@ export class SupervisorService implements OnModuleInit {
     // definitely stale (e.g. Disconnect webhook was dropped).
     private static readonly NON_CALL_AGENT_STATES = new Set(['ready', 'offline', 'paused']);
 
+    updateCallStatus(ucid: string, status: 'active' | 'on-hold') {
+        const call = this.activeCalls.get(ucid);
+        if (!call) {
+            this.logger.warn(`[CALL-STATUS] No active call found for UCID ${ucid}`);
+            return;
+        }
+        call.status = status;
+        this.activeCallSubject.next({ type: 'update', call, ucid });
+        this.logger.log(`[CALL-STATUS] ${ucid} → ${status} (agent=${call.agentId})`);
+    }
+
     getActiveCalls(): ActiveCall[] {
         // Sweep stale entries before returning. The activeCalls Map is a
         // best-effort in-memory projection of Ozonetel call events — if