Add frontend components for project/package/tag hierarchy views

- Create reusable UI components: Badge, Breadcrumb, Card, DataTable,
  FilterChip, Pagination, SearchInput, SortDropdown
- Update Home page with search, sort, filter, and pagination
- Update ProjectPage with package stats, format filtering, keyboard nav
- Update PackagePage with DataTable for tags, copy artifact ID, metadata
- Add TypeScript types for paginated responses and list params
- Update API client with pagination and filter query param support
- URL-based state persistence for all filter/sort/page params
- Keyboard navigation (Backspace to go up hierarchy)

frontend/src/components/index.ts

@@ -0,0 +1,9 @@
+export { Card, CardHeader, CardBody, CardFooter } from './Card';
+export { Badge } from './Badge';
+export { Breadcrumb } from './Breadcrumb';
+export { SearchInput } from './SearchInput';
+export { SortDropdown } from './SortDropdown';
+export type { SortOption } from './SortDropdown';
+export { FilterChip, FilterChipGroup } from './FilterChip';
+export { DataTable } from './DataTable';
+export { Pagination } from './Pagination';