feat(ui): show internal hostname and densify config UI

Add an application Internal access section that loads the running
container hostname (skipped for Compose apps), densify configuration
diff and popup-small defaults, dock the server-timing HUD into the
mobile top bar, restyle the 2FA challenge with the auth shell, and
enforce 16px mobile form fonts to prevent iOS zoom.

tests/v4/Browser/ApplicationConfigurationTest.php

@@ -31,6 +31,8 @@ it('shows application configuration sections and navigation', function () {
         ->assertSee('Environment Variables')
         ->assertSee('Danger Zone')
         ->assertSee('Application details')
+        ->assertSee('Internal access')
+        ->assertSee('Docker network')
         ->assertSee('Build pipeline')
         ->screenshot(filename: 'application-configuration-overview');
 });