fix(smartproxy): improve certificate manager mocking in tests, enhance IPv6 validation, and record initial bytes for connection metrics

test/test.metrics-new.ts

@@ -144,33 +144,51 @@ tap.test('should track throughput correctly', async (tools) => {
   
   // Clean up
   client.destroy();
-  await tools.delayFor(100);
-  
+
+  // Wait for connection cleanup with retry
+  for (let i = 0; i < 10; i++) {
+    await tools.delayFor(100);
+    if (metrics.connections.active() === 0) break;
+  }
+
   // Verify connection was cleaned up
   expect(metrics.connections.active()).toEqual(0);
 });
 
 tap.test('should track multiple connections and routes', async (tools) => {
   const metrics = smartProxyInstance.getMetrics();
-  
+
+  // Ensure we start with 0 connections
+  const initialActive = metrics.connections.active();
+  if (initialActive > 0) {
+    console.log(`Warning: Starting with ${initialActive} active connections, waiting for cleanup...`);
+    for (let i = 0; i < 10; i++) {
+      await tools.delayFor(100);
+      if (metrics.connections.active() === 0) break;
+    }
+  }
+
   // Create multiple connections
   const clients: net.Socket[] = [];
   const connectionCount = 5;
-  
+
   for (let i = 0; i < connectionCount; i++) {
     const client = new net.Socket();
-    
+
     await new Promise<void>((resolve, reject) => {
       client.connect(proxyPort, 'localhost', () => {
         resolve();
       });
-      
+
       client.on('error', reject);
     });
-    
+
     clients.push(client);
   }
-  
+
+  // Allow connections to be fully established and tracked
+  await tools.delayFor(100);
+
   // Verify active connections
   expect(metrics.connections.active()).toEqual(connectionCount);