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/lib/sub2api/client.ts

@@ -0,0 +1,102 @@
+import { getEnv } from '@/lib/config';
+import type { Sub2ApiUser, Sub2ApiRedeemCode } from './types';
+
+function getHeaders(idempotencyKey?: string): Record<string, string> {
+  const env = getEnv();
+  const headers: Record<string, string> = {
+    'Content-Type': 'application/json',
+    'x-api-key': env.SUB2API_ADMIN_API_KEY,
+  };
+  if (idempotencyKey) {
+    headers['Idempotency-Key'] = idempotencyKey;
+  }
+  return headers;
+}
+
+export async function getCurrentUserByToken(token: string): Promise<Sub2ApiUser> {
+  const env = getEnv();
+  const response = await fetch(`${env.SUB2API_BASE_URL}/api/v1/auth/me`, {
+    headers: {
+      Authorization: `Bearer ${token}`,
+    },
+  });
+
+  if (!response.ok) {
+    throw new Error(`Failed to get current user: ${response.status}`);
+  }
+
+  const data = await response.json();
+  return data.data as Sub2ApiUser;
+}
+
+export async function getUser(userId: number): Promise<Sub2ApiUser> {
+  const env = getEnv();
+  const response = await fetch(`${env.SUB2API_BASE_URL}/api/v1/admin/users/${userId}`, {
+    headers: getHeaders(),
+  });
+
+  if (!response.ok) {
+    if (response.status === 404) throw new Error('USER_NOT_FOUND');
+    throw new Error(`Failed to get user: ${response.status}`);
+  }
+
+  const data = await response.json();
+  return data.data as Sub2ApiUser;
+}
+
+export async function createAndRedeem(
+  code: string,
+  value: number,
+  userId: number,
+  notes: string,
+): Promise<Sub2ApiRedeemCode> {
+  const env = getEnv();
+  const response = await fetch(
+    `${env.SUB2API_BASE_URL}/api/v1/admin/redeem-codes/create-and-redeem`,
+    {
+      method: 'POST',
+      headers: getHeaders(`sub2apipay:recharge:${code}`),
+      body: JSON.stringify({
+        code,
+        type: 'balance',
+        value,
+        user_id: userId,
+        notes,
+      }),
+    },
+  );
+
+  if (!response.ok) {
+    const errorData = await response.json().catch(() => ({}));
+    throw new Error(`Recharge failed (${response.status}): ${JSON.stringify(errorData)}`);
+  }
+
+  const data = await response.json();
+  return data.redeem_code as Sub2ApiRedeemCode;
+}
+
+export async function subtractBalance(
+  userId: number,
+  amount: number,
+  notes: string,
+  idempotencyKey: string,
+): Promise<void> {
+  const env = getEnv();
+  const response = await fetch(
+    `${env.SUB2API_BASE_URL}/api/v1/admin/users/${userId}/balance`,
+    {
+      method: 'POST',
+      headers: getHeaders(idempotencyKey),
+      body: JSON.stringify({
+        operation: 'subtract',
+        amount,
+        notes,
+      }),
+    },
+  );
+
+  if (!response.ok) {
+    const errorData = await response.json().catch(() => ({}));
+    throw new Error(`Subtract balance failed (${response.status}): ${JSON.stringify(errorData)}`);
+  }
+}

src/lib/sub2api/types.ts

@@ -0,0 +1,23 @@
+export interface Sub2ApiUser {
+  id: number;
+  username: string;
+  email: string;
+  status: string; // "active", "banned", etc.
+  balance: number;
+}
+
+export interface Sub2ApiRedeemCode {
+  id: number;
+  code: string;
+  type: string;
+  value: number;
+  status: string;
+  used_by: number;
+  used_at: string;
+}
+
+export interface Sub2ApiResponse<T> {
+  code: number;
+  data?: T;
+  message?: string;
+}