Add loose: false to SWC config for Stimulus compatibility

Override Shakapacker's default loose: true setting with loose: false to ensure spec-compliant class transforms that work with Stimulus. Without this, Stimulus controllers fail silently even with keepClassNames: true. 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>

Author: justin808

config/swc.config.js

@@ -5,6 +5,9 @@ const customConfig = {
  jsc: {
  // Preserve class names for Stimulus controller discovery
  keepClassNames: true,
+ // Use spec-compliant transforms (override Shakapacker's loose: true default)
+ // This is required for Stimulus controllers to work correctly
+ loose: false,
  transform: {
  react: {
  // Use automatic runtime (React 17+) - no need to import React