chore: add counterscale analytics tracker

style: apply biome formatting + tweak install guide text contrast

style: apply biome formatting to codex provider files

fix: hardcode light-plus/dark-plus as Codex codeThemeId

fix: use valid Codex code theme IDs for import compatibility

feat: move Zed to coming soon, add Codex to provider list

feat: add Codex support to View Code dialog with variant tabs

feat: add Codex-aware install, dropdown, and toolbar actions

feat: add Codex icon and terminal preview component

feat: add Codex theme provider with per-variant copy support

feat(preview): add opt-in serif headings support for design system

feat(design-system): support theme fonts in preview

fix(web): restore sidebar width to 25rem after shadcn update

fix(web): enable scroll in design system preview pane

feat(design-system): rewrite preview as scrollable single-page with numbered sections