Fix Stimulus controller class name for SWC compatibility

SWC's keepClassNames option doesn't preserve anonymous class names.
Changed from 'export default class extends Controller' to
'export default class CommentsController extends Controller' to ensure
the class name is preserved for Stimulus registration.

This should fix the failing RSpec tests where Stimulus controllers
weren't being properly registered.

Author: justin808

client/app/controllers/comments_controller.js

@@ -7,7 +7,7 @@ import { mangle } from 'marked-mangle';
 marked.use(gfmHeadingId());
 marked.use(mangle());
 
-export default class extends Controller {
+export default class CommentsController extends Controller {
   static targets = ['commentList', 'commentAuthor', 'commentText', 'commentRefresh', 'alertDiv', 'errorList'];
 
   resetText() {