feat(viewer): photo viewer with zoom, navigation and deep link

Co-Authored-By: Claude Code <noreply@anthropic.com>

apps/viewer/src/i18n/locales/en.ts

@@ -14,6 +14,18 @@ export default {
     retry: 'Retry',
   },
   lang: { switch: 'Switch language' },
+  viewer: {
+    title: 'Photo viewer',
+    close: 'Close',
+    previous: 'Previous photo',
+    next: 'Next photo',
+    counter: '{current} / {total}',
+    likeCount: '{count} likes',
+    loadFailed: 'Failed to load image',
+    // PHOTO_NOT_PUBLIC 专用：not found / unpublished / hidden share one code (anti-enumeration).
+    photoUnavailable: 'Photo not found or unavailable',
+    backToAlbum: 'Back to album',
+  },
   route: { tokenLabel: 'Album token', photoLabel: 'Photo' },
   errors: {
     albumNotFound: 'Album not found',