feat: log backfill endpoint for desktop log panel

- LogStreamService: ring buffer (500 entries) + getRecentLogs() method
- SupervisorController: GET /api/supervisor/logs/recent returns buffered
  log entries so the desktop log panel shows history on tab open, not
  just live stream

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

src/logging/log-stream.service.ts

@@ -0,0 +1,61 @@
+import { ConsoleLogger } from '@nestjs/common';
+import { Subject } from 'rxjs';
+
+export type LogEntry = {
+    timestamp: string;
+    level: 'log' | 'error' | 'warn' | 'debug' | 'verbose';
+    context: string;
+    message: string;
+};
+
+// Singleton — created once in main.ts, accessed by the SSE controller
+// via LogStreamService.instance. NestJS DI isn't available at bootstrap
+// time (the logger is created before the container), so we use a static
+// instance instead of @Injectable().
+export class LogStreamService extends ConsoleLogger {
+    static readonly instance = new LogStreamService();
+    readonly logSubject = new Subject<LogEntry>();
+    private readonly buffer: LogEntry[] = [];
+    private static readonly MAX_BUFFER = 500;
+
+    getRecentLogs(limit = 200): LogEntry[] {
+        return this.buffer.slice(-limit);
+    }
+
+    private emit(level: LogEntry['level'], message: unknown, context?: string) {
+        const entry: LogEntry = {
+            timestamp: new Date().toISOString(),
+            level,
+            context: context ?? this.context ?? '',
+            message: typeof message === 'string' ? message : JSON.stringify(message),
+        };
+        this.buffer.push(entry);
+        if (this.buffer.length > LogStreamService.MAX_BUFFER) this.buffer.shift();
+        this.logSubject.next(entry);
+    }
+
+    log(message: unknown, context?: string) {
+        super.log(message, context);
+        this.emit('log', message, context);
+    }
+
+    error(message: unknown, stack?: string, context?: string) {
+        super.error(message, stack, context);
+        this.emit('error', message, context);
+    }
+
+    warn(message: unknown, context?: string) {
+        super.warn(message, context);
+        this.emit('warn', message, context);
+    }
+
+    debug(message: unknown, context?: string) {
+        super.debug(message, context);
+        this.emit('debug', message, context);
+    }
+
+    verbose(message: unknown, context?: string) {
+        super.verbose(message, context);
+        this.emit('verbose', message, context);
+    }
+}

src/main.ts

@@ -3,9 +3,11 @@ import type { NestExpressApplication } from '@nestjs/platform-express';
 import { join } from 'path';
 import { AppModule } from './app.module';
 import { ConfigService } from '@nestjs/config';
+import { LogStreamService } from './logging/log-stream.service';
 
 async function bootstrap() {
-    const app = await NestFactory.create<NestExpressApplication>(AppModule);
+    const logger = LogStreamService.instance;
+    const app = await NestFactory.create<NestExpressApplication>(AppModule, { logger });
     const config = app.get(ConfigService);
 
     app.enableCors({

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

@@ -1,6 +1,7 @@
 import { Controller, Get, Post, Body, Query, Sse, Logger } from '@nestjs/common';
 import { Observable, filter, map } from 'rxjs';
 import { SupervisorService } from './supervisor.service';
+import { LogStreamService } from '../logging/log-stream.service';
 
 @Controller('api/supervisor')
 export class SupervisorController {
@@ -13,6 +14,16 @@ 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];
@@ -66,4 +77,19 @@ export class SupervisorController {
             } as MessageEvent)),
         );
     }
+
+    @Get('logs/recent')
+    getRecentLogs(@Query('limit') limit?: string) {
+        return LogStreamService.instance.getRecentLogs(limit ? parseInt(limit, 10) : 200);
+    }
+
+    @Sse('logs/stream')
+    streamLogs(): Observable<MessageEvent> {
+        this.logger.log('[SSE] Log stream opened');
+        return LogStreamService.instance.logSubject.pipe(
+            map(entry => ({
+                data: JSON.stringify(entry),
+            } as MessageEvent)),
+        );
+    }
 }

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