Insert Babel rule before SWC rule for proper precedence

Use splice() to insert the Babel rule BEFORE the SWC rule in the rules
array. This ensures Babel handles .js files first, while SWC's more
general regex still matches .ts and .tsx files.

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

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

Author: justin808

config/webpack/commonWebpackConfig.js

@@ -73,20 +73,17 @@ if (scssConfigIndex === -1) {
 const commonWebpackConfig = () => {
   const config = merge({}, baseClientWebpackConfig, commonOptions, ignoreWarningsConfig);
 
-  // Find the SWC rule and restrict it to only TypeScript files
-  // Use Babel for all JavaScript files (SWC has compatibility issues with Stimulus)
+  // Find the SWC rule and get its include/exclude
   const swcRuleIndex = config.module.rules.findIndex(rule =>
     rule.test && /\.(ts|tsx|js|jsx|mjs|coffee)/.test(rule.test.toString())
   );
 
   if (swcRuleIndex !== -1) {
     const swcRule = config.module.rules[swcRuleIndex];
 
-    // Change SWC rule to only handle TypeScript files
-    swcRule.test = /\.(ts|tsx)(\.erb)?$/;
-
-    // Add Babel loader for all JavaScript files, using the same include/exclude as SWC
-    config.module.rules.push({
+    // Insert Babel rule BEFORE SWC rule so it matches .js files first
+    // This allows Babel to handle all JavaScript while SWC continues to match TypeScript
+    config.module.rules.splice(swcRuleIndex, 0, {
       test: /\.(js|jsx|mjs)(\.erb)?$/,
       include: swcRule.include,
       exclude: swcRule.exclude,