feat: add repository pattern, service layer architecture, and scheduler management

- Implement repository pattern for data access layer
- Add comprehensive service layer for business logic
- Create scheduler management system with health monitoring
- Add bounded buffer utility for memory management
- Enhance security audit logging with retention policies

app/api/dashboard/metrics/route.ts

@@ -22,8 +22,8 @@ function convertToMockChatSession(
     sentiment: string | null;
     messagesSent: number | null;
     avgResponseTime: number | null;
-    escalated: boolean;
-    forwardedHr: boolean;
+    escalated: boolean | null;
+    forwardedHr: boolean | null;
     initialMsg: string | null;
     fullTranscriptUrl: string | null;
     summary: string | null;