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/Pagination.css

@@ -0,0 +1,64 @@
+/* Pagination Component */
+.pagination {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 16px 0;
+  margin-top: 16px;
+}
+
+.pagination__info {
+  font-size: 0.8125rem;
+  color: var(--text-muted);
+}
+
+.pagination__controls {
+  display: flex;
+  align-items: center;
+  gap: 4px;
+}
+
+.pagination__btn {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  min-width: 32px;
+  height: 32px;
+  padding: 0 8px;
+  background: var(--bg-tertiary);
+  border: 1px solid var(--border-primary);
+  border-radius: var(--radius-md);
+  font-size: 0.8125rem;
+  color: var(--text-secondary);
+  cursor: pointer;
+  transition: all var(--transition-fast);
+}
+
+.pagination__btn:hover:not(:disabled) {
+  background: var(--bg-hover);
+  color: var(--text-primary);
+  border-color: var(--border-secondary);
+}
+
+.pagination__btn:disabled {
+  opacity: 0.4;
+  cursor: not-allowed;
+}
+
+.pagination__page--active {
+  background: var(--accent-primary);
+  border-color: var(--accent-primary);
+  color: white;
+}
+
+.pagination__page--active:hover {
+  background: var(--accent-primary);
+  border-color: var(--accent-primary);
+  color: white;
+}
+
+.pagination__ellipsis {
+  padding: 0 8px;
+  color: var(--text-muted);
+  font-size: 0.8125rem;
+}