feat(update-modal): display last 5 release notes instead of single

- Modified backend to fetch last 5 releases from GitHub API
- Updated frontend to iterate through and display multiple releases
- Added latest badge and publish date styling
- Added update.latestBadge translation key to all locales
- Maintains backward compatibility for single changelog display

locales/zh-CN.json

@@ -1214,6 +1214,7 @@
         "checkingUpdates": "正在检查更新...",
         "checkingMessage": "请稍候，正在检查最新版本。",
         "showNotifications": "显示更新通知",
+        "latestBadge": "最新",
         "updateProgress": {
             "preparing": "正在准备更新...",
             "installing": "正在安装更新...",
@@ -1538,4 +1539,4 @@
             "learnMore": "浏览器插件教程"
         }
     }
-}
+}