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.socket-handler-race.ts

@@ -1,12 +1,15 @@
 import { expect, tap } from '@git.zone/tstest/tapbundle';
 import * as net from 'net';
 import { SmartProxy } from '../ts/index.js';
+import { findFreePorts, assertPortsFree } from './helpers/port-allocator.js';
 
 tap.test('should handle async handler that sets up listeners after delay', async () => {
+  const [PORT] = await findFreePorts(1);
+
   const proxy = new SmartProxy({
     routes: [{
       name: 'delayed-setup-handler',
-      match: { ports: 7777 },
+      match: { ports: PORT },
       action: {
         type: 'socket-handler',
         socketHandler: async (socket, context) => {
@@ -41,7 +44,7 @@ tap.test('should handle async handler that sets up listeners after delay', async
   });
   
   await new Promise<void>((resolve, reject) => {
-    client.connect(7777, 'localhost', () => {
+    client.connect(PORT, 'localhost', () => {
       // Send initial data immediately - this tests the race condition
       client.write('initial-message\n');
       resolve();
@@ -78,6 +81,7 @@ tap.test('should handle async handler that sets up listeners after delay', async
   expect(response).toContain('RECEIVED: test-message');
   
   await proxy.stop();
+  await assertPortsFree([PORT]);
 });
 
 export default tap.start();