Codex app

# Codex app ### New features - Added skills to the `@` menu so you can insert them from the composer alongside other mentions. - `Cmd/Ctrl+F` now starts with your current text selection, which makes searching reviews and diffs faster, alongside broader review navigation improvements such as a refreshed file tree and percentage-based file tree resizing. - Added a branded loading shimmer while the app starts. ### Performance improvements and bug fixes - Improved collapsed diff summaries in review. - Fixed slash-command focus and composer alignment issues, and polished plugin cards and step details. - Additional performance improvements and bug fixes.