Use keepClassNames instead of env.targets for Stimulus

Changed approach to preserve class names which is what Stimulus needs
for proper controller registration and inheritance.

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

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

Author: justin808

config/swc.config.js

@@ -4,9 +4,8 @@ module.exports = {
       react: {
         runtime: "automatic"
       }
-    }
-  },
-  env: {
-    targets: "defaults and supports es6-class"
+    },
+    // Preserve ES6 classes for Stimulus compatibility
+    keepClassNames: true
   }
 };