feat(nftables): Add NFTables integration for kernel-level forwarding and update documentation, tests, and helper functions

test/test.port-mapping.ts

@@ -213,9 +213,11 @@ tap.test('should handle errors in port mapping functions', async () => {
   // The connection should fail or timeout
   try {
     await createTestClient(PROXY_PORT_START + 5, TEST_DATA);
-    expect(false).toBeTrue('Connection should have failed but succeeded');
+    // Connection should not succeed
+    expect(false).toBeTrue();
   } catch (error) {
-    expect(true).toBeTrue('Connection failed as expected');
+    // Connection failed as expected
+    expect(true).toBeTrue();
   }
 });