Address PR review feedback: fix bugs, security, and config issues

- Add .node-renderer-bundles/ to .gitignore (Node renderer cache)
- CommentsFeed: skip artificial delay in production, use configurable
  base URL, add error handling for fetch, tighten sanitize-html config
- RspackRscPlugin: clear cache on each compilation for watch mode
- View: use trace only in development
- rscWebpackConfig: safer file-loader option merge

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: justin808

.gitignore

@@ -57,6 +57,9 @@ client/app/bundles/comments/rescript/**/*.bs.js
 # Using React on Rails default directory
 /ssr-generated/
 
+# Node renderer bundle cache
+.node-renderer-bundles/
+
 # Generated React on Rails packs
 **/generated/**