Add RSCWebpackPlugin to client webpack config

RSCWebpackPlugin({ isServer: false }) on the client bundle scans for
'use client' files and adds them as entry points so they appear in the
client manifest (react-client-manifest.json). Without this, client
components referenced in RSC payloads wouldn't have matching chunks
in the client bundle.

clientReferences scoped to config.source_path, consistent with the
server bundle's scoping in serverWebpackConfig.js.

Reference: Pro dummy clientWebpackConfig.js:16-24.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: ihabadham

config/webpack/clientWebpackConfig.js

@@ -1,6 +1,9 @@
 // The source code including full typescript support is available at:
 // https://github.com/shakacode/react_on_rails_tutorial_with_ssr_and_hmr_fast_refresh/blob/master/config/webpack/clientWebpackConfig.js
 
+const path = require('path');
+const { config } = require('shakapacker');
+const { RSCWebpackPlugin } = require('react-on-rails-rsc/WebpackPlugin');
 const commonWebpackConfig = require('./commonWebpackConfig');
 const { getBundler } = require('./bundlerUtils');
 
@@ -22,6 +25,16 @@ const configureClient = () => {
   // client config is going to try to load chunks.
   delete clientConfig.entry['server-bundle'];
 
+  const clientReferencesDir = path.resolve(config.source_path || 'client/app');
+  clientConfig.plugins.push(
+    new RSCWebpackPlugin({
+      isServer: false,
+      clientReferences: [
+        { directory: clientReferencesDir, recursive: true, include: /\.(js|ts|jsx|tsx)$/ },
+      ],
+    }),
+  );
+
   return clientConfig;
 };