Enhance socket cleanup and management for improved connection handling

- Refactor cleanupSocket function to support options for immediate destruction, allowing drain, and grace periods.
- Introduce createIndependentSocketHandlers for better management of half-open connections between client and server sockets.
- Update various handlers (HTTP, HTTPS passthrough, HTTPS terminate) to utilize new cleanup and socket management functions.
- Implement custom timeout handling in socket setup to prevent immediate closure during keep-alive connections.
- Add tests for long-lived connections and half-open connection scenarios to ensure stability and reliability.
- Adjust connection manager to handle socket cleanup based on activity status, improving resource management.

ts/proxies/smart-proxy/port-manager.ts

@@ -65,7 +65,7 @@ export class PortManager {
     const server = plugins.net.createServer((socket) => {
       // Check if shutting down
       if (this.isShuttingDown) {
-        cleanupSocket(socket, 'port-manager-shutdown');
+        cleanupSocket(socket, 'port-manager-shutdown', { immediate: true });
         return;
       }