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/config.ts

@@ -0,0 +1,139 @@
+import { z } from 'zod';
+
+const optionalTrimmedString = z.preprocess((value) => {
+  if (typeof value !== 'string') return value;
+  const trimmed = value.trim();
+  return trimmed === '' ? undefined : trimmed;
+}, z.string().optional());
+
+const rawEnvSchema = z.object({
+  DATABASE_URL: z.string().min(1),
+
+  SUB2API_BASE_URL: z.string().url(),
+  SUB2API_ADMIN_API_KEY: z.string().min(1),
+
+  EASY_PAY_PID: optionalTrimmedString,
+  EASY_PAY_PKEY: optionalTrimmedString,
+  EASY_PAY_API_BASE: optionalTrimmedString,
+  EASY_PAY_NOTIFY_URL: optionalTrimmedString,
+  EASY_PAY_RETURN_URL: optionalTrimmedString,
+  EASY_PAY_CID: optionalTrimmedString,
+  EASY_PAY_CID_ALIPAY: optionalTrimmedString,
+  EASY_PAY_CID_WXPAY: optionalTrimmedString,
+
+  ZPAY_PID: optionalTrimmedString,
+  ZPAY_PKEY: optionalTrimmedString,
+  ZPAY_API_BASE: optionalTrimmedString,
+  ZPAY_NOTIFY_URL: optionalTrimmedString,
+  ZPAY_RETURN_URL: optionalTrimmedString,
+  ZPAY_CID: optionalTrimmedString,
+  ZPAY_CID_ALIPAY: optionalTrimmedString,
+  ZPAY_CID_WXPAY: optionalTrimmedString,
+
+  ENABLED_PAYMENT_TYPES: z.string().default('alipay,wxpay').transform(v => v.split(',').map(s => s.trim())),
+
+  ORDER_TIMEOUT_MINUTES: z.string().default('5').transform(Number).pipe(z.number().int().positive()),
+  MIN_RECHARGE_AMOUNT: z.string().default('1').transform(Number).pipe(z.number().positive()),
+  MAX_RECHARGE_AMOUNT: z.string().default('10000').transform(Number).pipe(z.number().positive()),
+  PRODUCT_NAME: z.string().default('Sub2API Balance Recharge'),
+
+  ADMIN_TOKEN: z.string().min(1),
+
+  NEXT_PUBLIC_APP_URL: z.string().url(),
+  NEXT_PUBLIC_PAY_HELP_IMAGE_URL: optionalTrimmedString,
+  NEXT_PUBLIC_PAY_HELP_TEXT: optionalTrimmedString,
+});
+
+const resolvedEnvSchema = z.object({
+  DATABASE_URL: z.string().min(1),
+  SUB2API_BASE_URL: z.string().url(),
+  SUB2API_ADMIN_API_KEY: z.string().min(1),
+
+  EASY_PAY_PID: z.string().min(1),
+  EASY_PAY_PKEY: z.string().min(1),
+  EASY_PAY_API_BASE: z.string().url(),
+  EASY_PAY_NOTIFY_URL: z.string().url(),
+  EASY_PAY_RETURN_URL: z.string().url(),
+  EASY_PAY_CID: optionalTrimmedString,
+  EASY_PAY_CID_ALIPAY: optionalTrimmedString,
+  EASY_PAY_CID_WXPAY: optionalTrimmedString,
+
+  ENABLED_PAYMENT_TYPES: z.array(z.string()),
+
+  ORDER_TIMEOUT_MINUTES: z.number().int().positive(),
+  MIN_RECHARGE_AMOUNT: z.number().positive(),
+  MAX_RECHARGE_AMOUNT: z.number().positive(),
+  PRODUCT_NAME: z.string(),
+
+  ADMIN_TOKEN: z.string().min(1),
+
+  NEXT_PUBLIC_APP_URL: z.string().url(),
+  NEXT_PUBLIC_PAY_HELP_IMAGE_URL: optionalTrimmedString,
+  NEXT_PUBLIC_PAY_HELP_TEXT: optionalTrimmedString,
+});
+
+export type Env = z.infer<typeof resolvedEnvSchema>;
+
+type RawEnv = z.infer<typeof rawEnvSchema>;
+
+function pickRequired(raw: RawEnv, key: keyof RawEnv, fallbackKey: keyof RawEnv): string {
+  const value = raw[key] ?? raw[fallbackKey];
+  if (!value) {
+    throw new Error(`Missing required env: ${String(key)} (fallback: ${String(fallbackKey)})`);
+  }
+  return value;
+}
+
+function pickOptional(raw: RawEnv, key: keyof RawEnv, fallbackKey: keyof RawEnv): string | undefined {
+  return raw[key] ?? raw[fallbackKey] ?? undefined;
+}
+
+let cachedEnv: Env | null = null;
+
+export function getEnv(): Env {
+  if (cachedEnv) return cachedEnv;
+
+  const parsed = rawEnvSchema.safeParse(process.env);
+  if (!parsed.success) {
+    console.error('Invalid environment variables:', parsed.error.flatten().fieldErrors);
+    throw new Error('Invalid environment variables');
+  }
+
+  const raw = parsed.data;
+  const resolved = {
+    DATABASE_URL: raw.DATABASE_URL,
+    SUB2API_BASE_URL: raw.SUB2API_BASE_URL,
+    SUB2API_ADMIN_API_KEY: raw.SUB2API_ADMIN_API_KEY,
+
+    EASY_PAY_PID: pickRequired(raw, 'EASY_PAY_PID', 'ZPAY_PID'),
+    EASY_PAY_PKEY: pickRequired(raw, 'EASY_PAY_PKEY', 'ZPAY_PKEY'),
+    EASY_PAY_API_BASE: pickRequired(raw, 'EASY_PAY_API_BASE', 'ZPAY_API_BASE'),
+    EASY_PAY_NOTIFY_URL: pickRequired(raw, 'EASY_PAY_NOTIFY_URL', 'ZPAY_NOTIFY_URL'),
+    EASY_PAY_RETURN_URL: pickRequired(raw, 'EASY_PAY_RETURN_URL', 'ZPAY_RETURN_URL'),
+    EASY_PAY_CID: pickOptional(raw, 'EASY_PAY_CID', 'ZPAY_CID'),
+    EASY_PAY_CID_ALIPAY: pickOptional(raw, 'EASY_PAY_CID_ALIPAY', 'ZPAY_CID_ALIPAY'),
+    EASY_PAY_CID_WXPAY: pickOptional(raw, 'EASY_PAY_CID_WXPAY', 'ZPAY_CID_WXPAY'),
+
+    ENABLED_PAYMENT_TYPES: raw.ENABLED_PAYMENT_TYPES,
+
+    ORDER_TIMEOUT_MINUTES: raw.ORDER_TIMEOUT_MINUTES,
+    MIN_RECHARGE_AMOUNT: raw.MIN_RECHARGE_AMOUNT,
+    MAX_RECHARGE_AMOUNT: raw.MAX_RECHARGE_AMOUNT,
+    PRODUCT_NAME: raw.PRODUCT_NAME,
+
+    ADMIN_TOKEN: raw.ADMIN_TOKEN,
+
+    NEXT_PUBLIC_APP_URL: raw.NEXT_PUBLIC_APP_URL,
+    NEXT_PUBLIC_PAY_HELP_IMAGE_URL: raw.NEXT_PUBLIC_PAY_HELP_IMAGE_URL,
+    NEXT_PUBLIC_PAY_HELP_TEXT: raw.NEXT_PUBLIC_PAY_HELP_TEXT,
+  };
+
+  const resolvedParsed = resolvedEnvSchema.safeParse(resolved);
+  if (!resolvedParsed.success) {
+    console.error('Invalid resolved env variables:', resolvedParsed.error.flatten().fieldErrors);
+    throw new Error('Invalid resolved env variables');
+  }
+
+  cachedEnv = resolvedParsed.data;
+  return cachedEnv;
+}