🎨 refactor(home): enhance notice modal UI and behavior

- Replace showNotice with Semi Modal component for better UI consistency
- Add "Close Today" and "Close" actions for flexible notice control
- Improve markdown rendering with marked.parse
- Add responsive modal size based on device type
- Implement max height with scrollable content (60vh)
- Style scrollbar to match Semi design system
- Remove old notice caching logic for more reliable notifications

web/src/i18n/locales/en.json

@@ -1526,5 +1526,8 @@
   "腾讯混元": "Hunyuan",
   "360智脑": "360 AI Brain",
   "零一万物": "Yi",
-  "豆包": "Doubao"
+  "豆包": "Doubao",
+  "系统公告": "System Notice",
+  "今日关闭": "Close Today",
+  "关闭公告": "Close Notice"
 }