feat: add danmuku plugin documentation and i18n setup guide

- Created a new documentation file for the danmuku plugin with code examples for usage.
- Added comprehensive language settings documentation, including default languages, importing languages, adding new languages, and modifying existing languages.
- Updated the i18n setup guide to reflect changes in language handling and provide code snippets for implementation.

docs/document/assets/index.md.qte4O2y_.lean.js

@@ -0,0 +1 @@
+import{_ as i,c as a,o as n,ak as l}from"./chunks/framework.xxfEszSJ.js";const g=JSON.parse('{"title":"安装使用","description":"","frontmatter":{},"headers":[],"relativePath":"index.md","filePath":"index.md","lastUpdated":1755403790000}'),p={name:"index.md"};function t(e,s,h,k,r,E){return n(),a("div",null,s[0]||(s[0]=[l("",50)]))}const c=i(p,[["render",t]]);export{g as __pageData,c as default};