feat: add page transition animations and loading indicators

- Add nextjs-toploader for instant top progress bar on navigation
- Add next-view-transitions for View Transitions API page transitions
- Enhance template.tsx page enter animation (0.45s, scale effect)
- Replace next/link with next-view-transitions Link for smooth transitions
- Add prefers-reduced-motion support for accessibility

Co-authored-by: Cursor <cursoragent@cursor.com>

components/repo-card.tsx

@@ -1,4 +1,4 @@
-import Link from 'next/link';
+import { Link } from 'next-view-transitions';
 import { FiExternalLink } from 'react-icons/fi';
 import type { RepoSummary } from '@/lib/github';
 import { getLanguageColor } from '@/lib/github-lang-colors';