docs: refine style and fixture comment accuracy

tests/fixtures/api-server.mjs

@@ -186,7 +186,7 @@ const server = createServer(async (request, response) => {
     return reply(response);
   }
   if (path === "/order/42" && request.method === "GET") {
-    // 余额、订单与支付状态共享paid事实，支付成功后回读必须反映已付金额。
+    // 订单未付金额、流水与支付状态共享 paid 标记，支付成功后回读反映已付金额。
     if (options.expiredPayment)
       return reply(
         response,
@@ -231,7 +231,7 @@ const server = createServer(async (request, response) => {
   if (path === "/voucher/pay" && request.method === "GET")
     return reply(response, { list: [] });
   if (path === "/pay" && request.method === "POST") {
-    // Paid是现有后端的顶层字段；挂起变体返回渠道HTML，随后状态查询不响应。
+    // Paid 是顶层 code 字段的支付状态值；挂起变体返回渠道 HTML，随后状态查询不响应。
     if (options.hangPaymentStatus)
       return reply(response, { html: '<div role="status">本地支付渠道</div>' });
     paid = true;