Remove package-lock.json from .gitignore to detect accidental npm usage

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

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

Author: justin808

.gitignore

@@ -48,9 +48,6 @@ client/app/libs/i18n/default.js
 yarn-debug.log*
 .yarn-integrity
 
-# npm lock file (project uses yarn)
-package-lock.json
-
 lib/bs
 /lib/ocaml