refactor(frontend): use @project-graphite/ui for the theme and shared components

[AmrMsCLL]

What changed

The frontend now takes its design tokens, base styles and generic components from the shared @project-graphite/ui package, installed from its v0.1.0 GitHub release. There should be no visible change.

• global.css imports @project-graphite/ui/theme.css and adds an @source line for the package's classes. It keeps only the poster, catalogue-row and cast-row styles.
• Removed, now imported from the package:
  • Icon, Dialog, ConfirmDialog, EmptyState, Field, Toggle, Pagination, SmoothImage, Outage;
  • snackbar.tsx and useDismiss.ts;
  • the generic skeletons;
  • errorMessage, isAbortError and timeAgo.
• Rebuilt on package components:
  • Shell → AppShell;
  • AccountMenu → Menu, which also adds arrow-key and Home/End navigation, and focus returns to the trigger on Escape;
  • NotificationBell → Popover;
  • YearPicker → GridListbox.
• App.tsx wraps the routes in UiProvider, so the package renders react-router links.
• Unchanged behaviour: every Pagination keeps the 500-page cap (maxPages={500}). Snackbar actions use href instead of to.
• package-lock.json: adds the package. It also syncs the frontend's root specs (@types/node, react-router), which were already exact in package.json.

Verification

• npm run lint, and npm test --workspace frontend: 11 files, 30 tests pass.

• npm run build --workspace frontend passes.

• CSS before and after: both builds have 553 rules, and they match one for one. The only differences are the renamed generic classes (notification-* → popover-*, account-menu → menu-panel, year-* → grid-*, poster-image → smooth-image), fixed radii, shadow, easing and heights that now come from variables with the same values, and col-span-5 → col-span-full in the five-column year grid.

• Image: docker build --target server app succeeds. The first attempt failed because rolldown's musl binding was missing, and two clean rebuilds passed. main built cleanly too. This PR's image job runs the build again.

• Manual check on the graphite-tracker-scratch stack:

  • the home page on desktop;
  • Discover at 375 px with the tab bar;
  • the year picker's bottom sheet on a phone.

  I couldn't sign in, so the account menu and the notification bell were only covered by the specs.

Checklist

• The change is focused and contains no credentials or generated secrets.
• Documentation and tests were updated when behavior changed.
• Deployment or rollback considerations are described when relevant. Merging deploys production through the Coolify webhook. To roll back, redeploy the previous sha- image tag in Coolify.