合并客户端真机预览链路

需求：将待审 Release 扫码验收与项目级真机入口并入登录、发布集成候选。

实现：合并 Main-owned 精确预览与提交映射能力，保留现有登录和一键发布边界。

src/lib/device-preview.ts

@@ -0,0 +1,25 @@
+import { hostApiFetch } from '@/lib/host-api';
+import type { DevicePreviewSnapshot } from '../../shared/device-preview';
+
+type DevicePreviewResponse = {
+  success: boolean;
+  preview?: DevicePreviewSnapshot;
+  error?: string;
+};
+
+export class DevicePreviewApiError extends Error {
+  constructor(message: string) {
+    super(message);
+    this.name = 'DevicePreviewApiError';
+  }
+}
+
+export async function fetchProjectDevicePreview(projectId: string): Promise<DevicePreviewSnapshot> {
+  const response = await hostApiFetch<DevicePreviewResponse>(
+    `/api/opencode/projects/${encodeURIComponent(projectId)}/device-preview`,
+  );
+  if (!response.success || !response.preview) {
+    throw new DevicePreviewApiError(response.error || '无法读取真机预览状态');
+  }
+  return response.preview;
+}