feat: integrate Stripe payment with bugfixes and active timeout cancellation

- Add Stripe payment provider with Checkout Session flow
- Payment provider abstraction layer (EasyPay + Stripe unified interface)
- Stripe webhook with proper raw body handling and signature verification
- Frontend: Stripe button with URL validation, anti-duplicate click, noopener
- Active timeout cancellation: query platform before expiring, recover paid orders
- Singleton Stripe client, idempotency keys, Math.round for amounts
- Handle async_payment events, return null for unknown webhook events
- Set Checkout Session expires_at aligned with order timeout
- Add cancelPayment to provider interface (Stripe: sessions.expire, EasyPay: no-op)
- Enable stripe in frontend payment type list

src/app/api/admin/refund/route.ts

@@ -17,10 +17,7 @@ export async function POST(request: NextRequest) {
     const parsed = refundSchema.safeParse(body);
 
     if (!parsed.success) {
-      return NextResponse.json(
-        { error: '参数错误', details: parsed.error.flatten().fieldErrors },
-        { status: 400 },
-      );
+      return NextResponse.json({ error: '参数错误', details: parsed.error.flatten().fieldErrors }, { status: 400 });
     }
 
     const result = await processRefund({
@@ -32,10 +29,7 @@ export async function POST(request: NextRequest) {
     return NextResponse.json(result);
   } catch (error) {
     if (error instanceof OrderError) {
-      return NextResponse.json(
-        { error: error.message, code: error.code },
-        { status: error.statusCode },
-      );
+      return NextResponse.json({ error: error.message, code: error.code }, { status: error.statusCode });
     }
     console.error('Refund error:', error);
     return NextResponse.json({ error: '退款失败' }, { status: 500 });