fix(后台本地预览): 会员档位保存按请求体回显

- 假后台读取 POST 请求体，把提交字段覆盖到对应档位行再回显，保存非 starter 档不再把表单与列表重置成 starter。
- 抽出 UNLIMITED_CONCURRENCY_THRESHOLD 常量，列表与回显共用同一哨兵。

scripts/admin-web-fake-api.mjs

@@ -4,6 +4,9 @@ import http from 'node:http';
 
 const port = Number(process.argv[2] ?? 8099);
 
+/** 与后端 `MEMBERSHIP_UNLIMITED_CONCURRENCY` 一致的假数据哨兵。 */
+const UNLIMITED_CONCURRENCY_THRESHOLD = 128;
+
 const admin = {
   subject: 'admin:local',
   username: 'owner',
@@ -473,7 +476,15 @@ const userDetail = {
   tags: ['vip', '内测'],
 };
 
-function route(pathname, method, url) {
+function parseJsonBody(requestBody) {
+  try {
+    return JSON.parse(requestBody);
+  } catch {
+    return null;
+  }
+}
+
+function route(pathname, method, url, requestBody = '') {
   if (pathname === '/admin/api/login' && method === 'POST') {
     return { token: 'local-fake-token', admin };
   }
@@ -756,7 +767,8 @@ function route(pathname, method, url) {
       periodPoints,
       modelAccess,
       concurrentJobLimit,
-      unlimitedConcurrency: concurrentJobLimit >= 128,
+      unlimitedConcurrency:
+        concurrentJobLimit >= UNLIMITED_CONCURRENCY_THRESHOLD,
       enabled,
     });
     const plans = [
@@ -766,10 +778,22 @@ function route(pathname, method, url) {
       plan('pro', '专业会员', 3, 29_900, 299_000, 3_650, 'full', 5, true),
       plan('max', '旗舰会员', 4, 69_900, 699_000, 8_650, 'full', 128, true),
     ];
-    // 本地预览不解析请求体：POST 统一回显 starter，仅用于页面回填。
-    return method === 'POST'
-      ? plans[1]
-      : { entries: plans, unlimitedConcurrencyThreshold: 128 };
+    // 本地预览按请求体回显被保存的档位：把提交字段覆盖到对应档位行，避免保存非 starter 档后表单被回填成 starter。
+    if (method === 'POST') {
+      const submitted = parseJsonBody(requestBody);
+      const target =
+        plans.find((entry) => entry.plan === submitted?.plan) ?? plans[1];
+      const merged = { ...target, ...(submitted ?? {}) };
+      return {
+        ...merged,
+        unlimitedConcurrency:
+          Number(merged.concurrentJobLimit) >= UNLIMITED_CONCURRENCY_THRESHOLD,
+      };
+    }
+    return {
+      entries: plans,
+      unlimitedConcurrencyThreshold: UNLIMITED_CONCURRENCY_THRESHOLD,
+    };
   }
   if (pathname === '/admin/api/profile/recharge-products') {
     const product = (
@@ -1152,13 +1176,25 @@ function route(pathname, method, url) {
 
 const server = http.createServer((request, response) => {
   const url = new URL(request.url ?? '/', `http://127.0.0.1:${port}`);
-  const payload = route(url.pathname, request.method ?? 'GET', url);
-  const body = JSON.stringify({ data: payload });
-  response.writeHead(200, {
-    'Content-Type': 'application/json; charset=utf-8',
-    'x-genarrative-response-envelope': 'v1',
+  const chunks = [];
+  request.on('data', (chunk) => {
+    chunks.push(chunk);
+  });
+  request.on('end', () => {
+    const requestBody = Buffer.concat(chunks).toString('utf8');
+    const payload = route(
+      url.pathname,
+      request.method ?? 'GET',
+      url,
+      requestBody,
+    );
+    const body = JSON.stringify({ data: payload });
+    response.writeHead(200, {
+      'Content-Type': 'application/json; charset=utf-8',
+      'x-genarrative-response-envelope': 'v1',
+    });
+    response.end(body);
   });
-  response.end(body);
 });
 
 server.listen(port, '127.0.0.1', () => {