fix(i18n): translate remaining German hardcoded strings in PhotoUpload

Replace 6 hardcoded German strings in PhotoUpload.tsx with t() calls:
- 'Tag verknüpfen' → t('photos.linkDay')
- 'Kein Tag' / 'Tag N' → t('photos.noDay') / t('photos.dayLabel')
- '{N} Foto(s) ausgewählt' → t('photos.photoSelected/photosSelected')
- 'bis zu 30 Fotos' hint → t('photos.fileTypeHint')
- 'Wird hochgeladen...' → t('common.uploading')

Add all 6 new keys to all 14 language files and update test
assertions from German strings to English equivalents.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

client/src/i18n/translations/es.ts

@@ -1294,6 +1294,12 @@ const es: Record<string, string> = {
   'photos.linkPlace': 'Vincular lugar',
   'photos.noPlace': 'Sin lugar',
   'photos.uploadN': 'Subida de {n} foto(s)',
+  'photos.linkDay': 'Vincular día',
+  'photos.noDay': 'Ningún día',
+  'photos.dayLabel': 'Día {number}',
+  'photos.photoSelected': 'Foto seleccionada',
+  'photos.photosSelected': 'Fotos seleccionadas',
+  'photos.fileTypeHint': 'JPG, PNG, WebP · máx. 10 MB · hasta 30 fotos',
   'admin.addons.catalog.memories.name': 'Fotos (Immich)',
   'admin.addons.catalog.memories.description': 'Comparte fotos de viaje a través de tu instancia de Immich',
   'admin.addons.catalog.mcp.name': 'MCP',