refactor(ui): adopt Nuxt UI prose styles and apply various fixes

Replaces custom `markdown.css` with the default prose styling from Nuxt UI to simplify the styling architecture. This commit also includes several other fixes and improvements:

- fix(members): Correctly
handle empty `graduateYear` strings in the member list.
- fix(layout): Wrap `NuxtPage` in a div to resolve page transition issues.
- feat(seo): Add a meta title to the homepage.
- docs(content): Correct
the title and add an image to an event page.

content/events/20251009-roulian-xiaoyouhui-20th.md

@@ -1,11 +1,13 @@
 ---
-title: "柔联校友会 20 届历史就职典礼"
+title: "柔联校友会 20 届理事就职典礼"
 subtitle: "中学生写作比赛颁奖" 
 date: "2025-10-09"
 location: "富华冷气酒家 2 楼"
 cover: "/events/20251009-roulian-xiaoyouhui-20th/event-photo-1.jpg"
 ---
-# 柔联校友会 20 届历史就职典礼
+# 柔联校友会 20 届理事就职典礼
+
+![新届理事合照](/events/20251009-roulian-xiaoyouhui-20th/event-photo-1.jpg)
 
 柔佛州华校校友联合会日前举办第 20 届理事就职典礼与 2025 年 “林赛花教育基金” 柔佛州中学生现场写作比赛颁奖典礼，由马来西亚华校校友会联合总会会长萧成兴担任监誓人。