feat(english): 添加英语学习笔记文档和导航配置

添加英语学习相关文档，包括基础配置、词汇、语法、听说读写等模块
更新导航栏和侧边栏配置以支持英语学习笔记
修改首页标题和描述以更符合内容定位

docs/.vuepress/notes.ts

@@ -27,6 +27,48 @@ const cPlusPlus = defineNoteConfig({
     }
   ]
 })
+const english = defineNoteConfig({
+  dir: 'subject',
+  link: '/subject/english/',
+  sidebar: [
+    { text: "英语学习笔记", link: "/subject/english/" },
+    {
+      text: "学习环境与工具", prefix: "/basis", items: [
+        { text: "英语环境配置", link: "/subject/english/basis/" }
+      ]
+    },
+    {
+      text: "词汇与记忆", prefix: "/vocabulary", items: [
+        { text: "词汇学习与记忆法", link: "/subject/english/vocabulary/" }
+      ]
+    },
+    {
+      text: "语法与句法", prefix: "/grammar", items: [
+        { text: "核心语法与句型", link: "/subject/english/grammar/" }
+      ]
+    },
+    {
+      text: "听力与口语", prefix: "/listening-speaking", items: [
+        { text: "听力口语训练", link: "/subject/english/listening-speaking/" }
+      ]
+    },
+    {
+      text: "阅读与写作", prefix: "/reading-writing", items: [
+        { text: "阅读写作提升", link: "/subject/english/reading-writing/" }
+      ]
+    },
+    {
+      text: "考试与备考", prefix: "/exam", items: [
+        { text: "英语四级 (CET-4) 备考指南", link: "/subject/english/exam/cet-4/" }
+      ]
+    },
+    {
+      text: "资源与工具", prefix: "/resources", items: [
+        { text: "学习资源与工具", link: "/subject/english/resources/" }
+      ]
+    }
+  ]
+})
 const solidity = defineNoteConfig({
   dir: 'programming',
   link: '/programming/solidity/',
@@ -88,5 +130,5 @@ const linux = defineNoteConfig({
 export default defineNotesConfig({
   dir: 'notes',
   link: '/',
-  notes: [LeetCode, cPlusPlus, solidity, blockchain, linux],
+  notes: [LeetCode, english, cPlusPlus, solidity, blockchain, linux],
 })