refactor(docs): consolidate stage-0 into stage-1 and update routing

- Update homepage links in zh-cn and zh-tw to point to stage-1
- Update internal navigation links within stage-1 index files
- Remove obsolete github-pages-deployment document
- Update sitemap generation script to reflect stage-0 removal

docs/zh-cn/index.md

@@ -17,7 +17,7 @@ hero:
   actions:
     - theme: brand
       text: 开始一起 vibe！
-      link: /zh-cn/stage-0/0.1-learning-map/
+      link: /zh-cn/stage-1/learning-map/
     - theme: alt
       text: GitHub 加速更新
       link: https://github.com/datawhalechina/easy-vibe