feat: migrate payment provider to easy-pay, add order history and refund support

- Replace zpay with easy-pay payment provider (new lib/easy-pay/ module)
- Add order history page for users (pay/orders)
- Add GET /api/orders/my endpoint to list user's own orders
- Add GET /api/users/[id] endpoint for sub2api user lookup
- Add order status tracking module (lib/order/status.ts)
- Update config to support easy-pay credentials (merchant ID, key, gateway)
- Update PaymentForm and PaymentQRCode components for easy-pay flow
- Update pay page and admin page with new order management UI
- Update order service to support easy-pay, cancellation, and refund

src/app/api/user/route.ts

@@ -0,0 +1,37 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getUser } from '@/lib/sub2api/client';
+import { getEnv } from '@/lib/config';
+
+export async function GET(request: NextRequest) {
+  const userId = Number(request.nextUrl.searchParams.get('user_id'));
+  if (!userId || isNaN(userId) || userId <= 0) {
+    return NextResponse.json({ error: '无效的用户 ID' }, { status: 400 });
+  }
+
+  try {
+    const env = getEnv();
+    const user = await getUser(userId);
+
+    return NextResponse.json({
+      user: {
+        id: user.id,
+        username: user.username,
+        email: user.email,
+        status: user.status,
+        balance: user.balance,
+      },
+      config: {
+        enabledPaymentTypes: env.ENABLED_PAYMENT_TYPES,
+        minAmount: env.MIN_RECHARGE_AMOUNT,
+        maxAmount: env.MAX_RECHARGE_AMOUNT,
+      },
+    });
+  } catch (error) {
+    const message = error instanceof Error ? error.message : String(error);
+    if (message === 'USER_NOT_FOUND') {
+      return NextResponse.json({ error: '用户不存在' }, { status: 404 });
+    }
+    console.error('Get user error:', error);
+    return NextResponse.json({ error: '获取用户信息失败' }, { status: 500 });
+  }
+}