Apply prettier-compatible formatting across the repo to match the
incoming oxfmt configuration. Mechanical reformat only — no logic
changes. Covers YAML quote normalization, package.json key sorting,
Markdown/TOML formatting, and minor TS whitespace tweaks.
Replace lucide file icons with colored SVGs from material-icon-theme covering
53 language/filetype-specific icons. Add chevron expand indicators for
directories, indent guide lines, rounded rows, and restyle the header toolbar
to match the git diff pane pattern.
