Complete Babel cleanup and add React Refresh to SWC config

- Remove @babel/core direct dependency (still used by Jest, which is fine)
- Add React Refresh configuration to swc.config.js:
  - Enable development mode in development environment
  - Enable Fast Refresh for hot module replacement
- This ensures React Fast Refresh works properly with SWC

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

Co-Authored-By: Claude <[email protected]>

Author: justin808

spec/dummy/config/swc.config.js

@@ -7,6 +7,8 @@ module.exports = {
     transform: {
       react: {
         runtime: 'automatic',
+        development: process.env.NODE_ENV === 'development',
+        refresh: process.env.NODE_ENV === 'development', // Enable Fast Refresh in development
       },
     },
   },

spec/dummy/package.json

@@ -28,7 +28,6 @@
     "regenerator-runtime": "^0.13.4"
   },
   "devDependencies": {
-    "@babel/core": "7.17.9",
     "@pmmmwh/react-refresh-webpack-plugin": "^0.5.1",
     "@rescript/react": "^0.13.0",
     "@types/react": "^19.0.0",