chore(ui): re-sync UI components with the @nebari registry

[jbouder]

Re-syncs ui/ with the published @nebari registry as part of the cross-repo audit.

Part of nebari-dev/nebari-design#143
Closes #21

What changed

Alias drift (chore(ui): move components to the src/components/ui alias)

• components.json ui alias @/ui → @/components/ui; src/ui/ moved to src/components/ui/ and every import rewritten (tests included).
• Root tsconfig.json gains the @/* path mapping. shadcn add reads aliases from it and, without the mapping, wrote the installed files to a literal @/ directory instead of src/.
• avatar.tsx is not a registry item (there is no @nebari/avatar), so it moved out of components/ui/ to the app-owned src/components/avatar.tsx.
• copyText() was appended to the registry's src/lib/utils.ts; it now lives in src/lib/clipboard.ts so utils.ts is registry-identical.

Registry re-sync (chore(ui): re-sync @nebari registry components)

• Re-added with --overwrite: alert, badge, button, card, checkbox, code-block, dialog, dropdown-menu, field, input, label, navigation-menu, radio-group, select, slider, spinner, switch, table, tabs, textarea, toast, tooltip, utils, use-theme-preference (hook + theme provider).
• Newly installed: @nebari/claude-skill → ui/.claude/skills/nebari-ui/SKILL.md.
• The registry toast exports the Base UI manager directly (priority is derived from the toast type) instead of toast.success() / toast.error() wrappers; all 20 call sites now use toast.add({ type, title, description }).

Theme (chore(ui): adopt the @nebari/theme surface tokens)

• src/index.css is rebuilt from the registry globals.css: adds --canvas / --header surface tokens, the --info pair, --zinc-975, --duration-loading and the skeleton pulse animation, and takes the registry's current dark --popover / --muted values.
• Only two documented departures remain: the branding-driven derivations of --primary-hover and the sidebar tokens (guarded by tests/lib/index-css.test.ts), and the skill's app-defined header tokens (--header-border, --header-action-hover, --notification-badge, --sign-out-foreground) with their @theme inline mappings.
• Header paints with bg-header text-header-foreground; the page body with bg-canvas. --header-border defaults to var(--border) so the bar renders as the canonical border-border while the headerBorder branding override still works.
• The public /config.json keys headerBackground / bodyBackground keep their names and are mapped to --header / --canvas in lib/branding.ts, so existing operator branding keeps working. Chart values and docs are unchanged.

Verification

Every registry-owned file was compared byte-for-byte against registry/nebari/ at the time of the sync:

• Byte-identical: alert, badge, card, checkbox, code-block, field, input, label, radio-group, select, slider, spinner, switch, table, tabs, textarea, tooltip, lib/utils.ts, hooks/use-theme-preference.ts, hooks/theme-provider.tsx, .claude/skills/nebari-ui/SKILL.md.
• Identical apart from the import alias rewrite shadcn performs (@/ui/… → @/components/ui/…): button, dialog, dropdown-menu, navigation-menu, toast.

Gates: npm run build (tsc -b + vite) passes; npm test passes (5 files, 51 tests).

Note for future syncs: any shadcn add of a @nebari item also re-applies the theme item, which appends flattened tokens into src/index.css and duplicates the keyframes inside @theme inline. Revert src/index.css after adding components and merge theme changes by hand (or git checkout src/index.css).

#143 checklist for this repo

• components.json declares the @nebari registry and style: base-vega
• ui alias points at @/components/ui; components live in src/components/ui/
• All installed registry items re-added with --overwrite and verified against the registry
• @nebari/utils is unmodified (app helpers live outside it)
• @nebari/use-theme-preference installed and used for theme state
• @nebari/claude-skill installed at the frontend root
• @nebari/theme tokens adopted (--canvas, --header, --info, …), with app departures documented in the file header
• No orphan non-registry files in components/ui/ (avatar moved to src/components/)
• No hard-coded colors in app code outside components/ui/ (the only rgba(...) is the theme picker's data-checked shadow, verbatim from the skill's header recipe)
• App header matches the skill's canonical recipe (h-14 pl-4, h-8 w-auto logo with aria-label="Go to homepage", MenuBarActions gap-2, DropdownMenu modal={false}, 248px profile menu, menuitemradio theme picker wired to useTheme, text-sign-out-foreground sign-out). No follow-up issue needed.
• @base-ui/react at ^1.7.0 (satisfies the registry's ^1.6.0; unchanged)
• Biome/formatter — this frontend has no lint/format tooling, so nothing to align (out of scope here)

🤖 Generated with Claude Code