Add React 19 webpack config to Pro dummy app

Missing conditionNames configuration was causing Pro dummy tests to fail.
The Pro dummy uses Node renderer and needs the React 19 webpack setup.

Fixes CI failures in:
- examples (3.4, latest)
- examples (3.2, minimum)
- dummy-app-integration-tests

Author: justin808

react_on_rails_pro/spec/dummy/config/webpack/serverWebpackConfig.js

@@ -118,11 +118,21 @@ const configureServer = (rscBundle = false) => {
 
   // If using the default 'web', then libraries like Emotion and loadable-components
   // break with SSR. The fix is to use a node renderer and change the target.
-  // If using the React on Rails Pro node server renderer, uncomment the next line
+  // React 19 requires target: 'node' to properly handle Node.js built-in modules
   serverWebpackConfig.target = 'node';
 
   serverWebpackConfig.node = false;
 
+  // React 19 Fix: Prevent webpack from resolving to react-server condition
+  // The server-bundle needs the full React with hooks for SSR, not the react-server build
+  // Explicitly set conditionNames without react-server
+  if (!serverWebpackConfig.resolve) {
+    serverWebpackConfig.resolve = {};
+  }
+  // For target: 'node', webpack defaults to ['node', 'import', 'require', 'default']
+  // We explicitly list them to ensure react-server is not included
+  serverWebpackConfig.resolve.conditionNames = ['node', 'import', 'require', 'default'];
+
   return serverWebpackConfig;
 };