fix: align dashboard host warnings with effective bind

tests/unit/web-server/start-server-host.test.ts

@@ -18,6 +18,14 @@ afterEach(async () => {
 });
 
 describe('startServer host binding', () => {
+  it('binds with system-default host when no host is provided', async () => {
+    const instance = await startServer({ port: 0 });
+    instances.push(instance);
+
+    const address = instance.server.address() as AddressInfo;
+    expect(address.port).toBeGreaterThan(0);
+  });
+
   it('binds to an explicit loopback host', async () => {
     const instance = await startServer({ port: 0, host: '127.0.0.1' });
     instances.push(instance);