fix(photos): fix SQL type mismatch, pagination panic, missing icons, and add day/month/year grouping

- Fix photos endpoint 500: remove ::uuid cast on user_id WHERE clause (VARCHAR column)
- Fix pagination underflow panic when total_pages is 0
- Add missing 'images' and 'play' icons to SVG icon registry
- Add day/month/year grouping toggle with localStorage persistence
- Improve grid spacing and group header styling per mode
- Add i18n translations for grouping labels (all 9 locales)

src/interfaces/nextcloud/report_handler.rs

@@ -265,6 +265,7 @@ fn file_dto_from_search(fr: &crate::application::dtos::search_dto::SearchFileRes
         category: category_for(&fr.name, &fr.mime_type).to_string().into(),
         size_formatted: format_file_size(fr.size),
         owner_id: None,
+        sort_date: None,
     }
 }