added new di with connection pool and rebuild of the database/cache services

libs/postgres-client/src/index.ts

@@ -28,6 +28,9 @@ export type {
   Strategy,
   RiskLimit,
   AuditLog,
+  PoolMetrics,
+  ConnectionEvents,
+  DynamicPoolConfig,
 } from './types';
 
 // Factory functions
@@ -36,9 +39,4 @@ export {
   createAndConnectPostgreSQLClient,
 } from './factory';
 
-// Singleton instance
-export {
-  getPostgreSQLClient,
-  connectPostgreSQL,
-  disconnectPostgreSQL,
-} from './singleton';
+// Singleton pattern removed - use factory functions instead