Implement proxy chain connection accumulation fix and add comprehensive tests

- Updated socket handling to prevent connection accumulation in chained proxies.
- Introduced centralized bidirectional forwarding for consistent socket management.
- Enhanced cleanup logic to ensure immediate closure of sockets when one closes.
- Added tests to verify connection behavior under various scenarios, including backend failures and rapid reconnections.

ts/proxies/smart-proxy/http-proxy-bridge.ts

@@ -1,5 +1,6 @@
 import * as plugins from '../../plugins.js';
 import { HttpProxy } from '../http-proxy/index.js';
+import { setupBidirectionalForwarding } from '../../core/utils/socket-utils.js';
 import type { IConnectionRecord, ISmartProxyOptions } from './models/interfaces.js';
 import type { IRouteConfig } from './models/route-types.js';
 
@@ -123,36 +124,25 @@ export class HttpProxyBridge {
       proxySocket.write(initialChunk);
     }
     
-    // Pipe the sockets together
-    socket.pipe(proxySocket);
-    proxySocket.pipe(socket);
-    
-    // Handle cleanup
-    let cleanedUp = false;
-    const cleanup = (reason: string) => {
-      if (cleanedUp) return;
-      cleanedUp = true;
-      
-      // Remove all event listeners to prevent memory leaks
-      socket.removeAllListeners('end');
-      socket.removeAllListeners('error');
-      proxySocket.removeAllListeners('end');
-      proxySocket.removeAllListeners('error');
-      
-      socket.unpipe(proxySocket);
-      proxySocket.unpipe(socket);
-      
-      if (!proxySocket.destroyed) {
-        proxySocket.destroy();
-      }
-      
-      cleanupCallback(reason);
-    };
-    
-    socket.on('end', () => cleanup('socket_end'));
-    socket.on('error', () => cleanup('socket_error'));
-    proxySocket.on('end', () => cleanup('proxy_end'));
-    proxySocket.on('error', () => cleanup('proxy_error'));
+    // Use centralized bidirectional forwarding
+    setupBidirectionalForwarding(socket, proxySocket, {
+      onClientData: (chunk) => {
+        // Update stats if needed
+        if (record) {
+          record.bytesReceived += chunk.length;
+        }
+      },
+      onServerData: (chunk) => {
+        // Update stats if needed
+        if (record) {
+          record.bytesSent += chunk.length;
+        }
+      },
+      onCleanup: (reason) => {
+        cleanupCallback(reason);
+      },
+      enableHalfOpen: false // Close both when one closes (required for proxy chains)
+    });
   }
   
   /**