🧹 清理重复配置文件

- 删除根目录中重复的 NestJS 配置文件
- 删除 tsconfig.json, tsconfig.build.json, eslint.config.mjs, .prettierrc
- 保留 wwjcloud-nest/ 目录中的完整配置
- 避免配置冲突，确保项目结构清晰

admin-vben/src/layout/admin/components/header/switch-lang.vue

@@ -0,0 +1,32 @@
+<template>
+    <el-dropdown @command="switchLang" :tabindex="1">
+        <icon name="iconfont iconfanyi" />
+        <template #dropdown>
+            <el-dropdown-menu>
+                <el-dropdown-item command="zh-cn" :disabled="systemStore.lang == 'zh-cn'">简体中文</el-dropdown-item>
+                <el-dropdown-item command="en" :disabled="systemStore.lang == 'en'">English</el-dropdown-item>
+            </el-dropdown-menu>
+        </template>
+    </el-dropdown>
+</template>
+
+<script lang="ts" setup>
+import useSystemStore from '@/stores/modules/system'
+import { language } from '@/lang'
+import { useRoute } from 'vue-router'
+import storage from '@/utils/storage'
+
+const route = useRoute()
+const systemStore = useSystemStore()
+
+const switchLang = (command: string) => {
+    systemStore.$patch((state) => {
+        state.lang = command
+        storage.set({ key: 'lang', data: command })
+    })
+    language.loadLocaleMessages(route.path, systemStore.lang)
+    location.reload()
+}
+</script>
+
+<style lang="scss" scoped></style>