Address code review feedback

Fixed issues identified in code review:

1. **Fixed babel.config.js comment** - Corrected misleading comment about
   @babel/preset-react location (it IS in devDependencies)

2. **Restored environment-aware development mode** - Changed from always-true
   to !isProductionEnv to match previous behavior and avoid inconsistent
   test results in production builds

3. **Removed unused dependency** - Removed babel-plugin-transform-react-remove-prop-types
   which was no longer used after removing Babel plugins from config

4. **Security audit complete** - Ran yarn audit; found 9 pre-existing
   vulnerabilities in dev dependencies (axios, webpack-dev-server,
   resolve-url-loader). These are not introduced by this PR and are
   low/moderate severity in dev-only packages.

Remaining items from #678 (out of scope for this PR):
- SWC dependency updates (1.13.5 and 0.2.6 are latest available)
- Dual-transpiler testing (Jest uses Babel, webpack uses SWC)
- ajv dependency documentation
- Performance metrics

These can be addressed in separate PRs as needed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

babel.config.js

@@ -3,16 +3,18 @@
 module.exports = function (api) {
   const defaultConfigFunc = require('shakapacker/package/babel/preset.js');
   const resultConfig = defaultConfigFunc(api);
+  const isProductionEnv = api.env('production');
 
-  // Add React preset for Jest testing
-  // Note: @babel/preset-react is in devDependencies since it's only needed for testing
+  // Add React preset for Jest testing and ESLint
+  // Note: @babel/preset-react is in devDependencies (only needed for Jest/ESLint, not webpack)
   const changesOnDefault = {
     presets: [
       [
         '@babel/preset-react',
         {
           runtime: 'automatic',
-          development: true, // Always use development mode for better test error messages
+          // Use development mode for better error messages in tests and development
+          development: !isProductionEnv,
           useBuiltIns: true,
         },
       ],

package.json

@@ -48,7 +48,6 @@
     "ajv": "^8.17.1",
     "autoprefixer": "^10.4.14",
     "axios": "^0.21.1",
-    "babel-plugin-transform-react-remove-prop-types": "^0.4.24",
     "classnames": "^2.3.2",
     "compression-webpack-plugin": "10.0.0",
     "css-loader": "^6.7.3",

yarn.lock

@@ -2902,11 +2902,6 @@ babel-plugin-polyfill-regenerator@^0.6.5:
   dependencies:
     "@babel/helper-define-polyfill-provider" "^0.6.5"
 
-babel-plugin-transform-react-remove-prop-types@^0.4.24:
-  version "0.4.24"
-  resolved "https://registry.npmjs.org/babel-plugin-transform-react-remove-prop-types/-/babel-plugin-transform-react-remove-prop-types-0.4.24.tgz"
-  integrity sha512-eqj0hVcJUR57/Ug2zE1Yswsw4LhuqqHhD+8v120T1cl3kjg76QwtyBrdIk4WVwK+lAhBJVYCd/v+4nc4y+8JsA==
-
 babel-preset-current-node-syntax@^1.0.0:
   version "1.2.0"
   resolved "https://registry.npmjs.org/babel-preset-current-node-syntax/-/babel-preset-current-node-syntax-1.2.0.tgz"