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)

static/locales/zh.json

@@ -14,7 +14,10 @@
   "photos": {
     "empty_state": "还没有照片",
     "empty_hint": "上传图片或视频即可在此查看",
-    "items_selected": "已选择"
+    "items_selected": "已选择",
+    "view_daily": "日",
+    "view_monthly": "月",
+    "view_yearly": "年"
   },
   "actions": {
     "search": "搜索文件...",