feat: 迁入 MiGu.Server、平台前端与车辆列表 reflection 回退

从 Simple-FR 拆出 Platform.Server 并重命名为 MiGu.Server；frontends 源码与构建脚本迁入本仓库。地图监控在 projection/cars 失败或为空时回退 reflection 车辆列表；Simple 仓库已移除旧 Platform.Server。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontends/apps/simple-platform-vue/env.d.ts

@@ -0,0 +1,18 @@
+/// <reference types="vite/client" />
+
+declare module '*.vue' {
+  import type { DefineComponent } from 'vue'
+  const component: DefineComponent<Record<string, unknown>, Record<string, unknown>, unknown>
+  export default component
+}
+
+interface ImportMetaEnv {
+  readonly VITE_API_BASE: string
+  readonly VITE_VRENDER_HOST: string
+  // 'true' = 走前端 mock；其余值（含未设置）一律走真实后端。
+  readonly VITE_USE_MOCK?: string
+}
+
+interface ImportMeta {
+  readonly env: ImportMetaEnv
+}