fix(rustproxy): Use cooperative cancellation for background tasks, prune stale caches and metric entries, and switch tests to dynamic port allocation to avoid port conflicts

test/test.port-forwarding-fix.ts

@@ -1,17 +1,19 @@
 import { expect, tap } from '@git.zone/tstest/tapbundle';
 import * as net from 'net';
 import { SmartProxy } from '../ts/proxies/smart-proxy/smart-proxy.js';
+import { findFreePorts, assertPortsFree } from './helpers/port-allocator.js';
 
 let echoServer: net.Server;
 let proxy: SmartProxy;
 
-const ECHO_PORT = 47400;
-const PROXY_PORT_1 = 47401;
-const PROXY_PORT_2 = 47402;
+let ECHO_PORT: number;
+let PROXY_PORT_1: number;
+let PROXY_PORT_2: number;
 
 tap.test('port forwarding should not immediately close connections', async (tools) => {
   // Set a timeout for this test
   tools.timeout(10000); // 10 seconds
+  [ECHO_PORT, PROXY_PORT_1, PROXY_PORT_2] = await findFreePorts(3);
   // Create an echo server
   echoServer = await new Promise<net.Server>((resolve, reject) => {
     const server = net.createServer((socket) => {
@@ -96,6 +98,7 @@ tap.test('cleanup', async () => {
       });
     });
   }
+  await assertPortsFree([ECHO_PORT, PROXY_PORT_1, PROXY_PORT_2]);
 });
 
 export default tap.start();