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/src/components/PermissionGuard.vue

@@ -0,0 +1,27 @@
+<template>
+  <template v-if="visibility === 'interactive'">
+    <slot />
+  </template>
+  <div v-else-if="visibility === 'readonly'" class="pg-readonly" :title="`${widgetId} 当前为只读`">
+    <slot />
+    <div class="pg-mask" />
+  </div>
+  <!-- hidden: 不渲染任何内容 -->
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue'
+import { useAuthStore } from '@/stores/auth'
+
+const props = defineProps<{ widgetId: string }>()
+const auth = useAuthStore()
+const visibility = computed(() => auth.widgetOf(props.widgetId))
+</script>
+
+<style scoped>
+.pg-readonly { position: relative; }
+.pg-mask {
+  position: absolute; inset: 0; background: rgba(255, 255, 255, 0.3);
+  pointer-events: all; cursor: not-allowed;
+}
+</style>