Add user sync API with Redis integration

Implement GET and POST endpoints for user sync data with Redis.

app/api/user/sync/route.ts

@@ -0,0 +1,46 @@
+import { Redis } from '@upstash/redis';
+import { NextRequest, NextResponse } from 'next/server';
+
+// 确保这行代码在整个文件中只出现一次
+export const runtime = 'edge';
+
+const redis = Redis.fromEnv();
+
+export async function GET(request: NextRequest) {
+  const profileId = request.headers.get('x-profile-id');
+  
+  if (!profileId) {
+    return NextResponse.json({ error: 'Missing profileId' }, { status: 400 });
+  }
+
+  try {
+    const data = await redis.get(`user:sync:${profileId}`);
+    return NextResponse.json({ 
+      success: true, 
+      data: data || { history: [], favorites: [] } 
+    });
+  } catch (error) {
+    console.error('Redis Get Error:', error);
+    return NextResponse.json({ error: 'Failed to fetch sync data' }, { status: 500 });
+  }
+}
+
+export async function POST(request: NextRequest) {
+  const profileId = request.headers.get('x-profile-id');
+  
+  if (!profileId) {
+    return NextResponse.json({ error: 'Missing profileId' }, { status: 400 });
+  }
+
+  try {
+    const body = await request.json();
+    const { history, favorites } = body;
+
+    await redis.set(`user:sync:${profileId}`, { history, favorites });
+
+    return NextResponse.json({ success: true });
+  } catch (error) {
+    console.error('Redis Set Error:', error);
+    return NextResponse.json({ error: 'Failed to save sync data' }, { status: 500 });
+  }
+}