feat(prototype): rename web app to procurement service

docs/design/web-task-workbench.html

@@ -4,7 +4,7 @@
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width, initial-scale=1">
   <link rel="icon" href="data:,">
-  <title>采购任务 · cmbuyer 原型</title>
+  <title>采购任务 · 采购服务原型</title>
   <style>
     :root {
       --bg:#f4f7fb; --surface:#fff; --subtle:#f8fafc; --text:#172033; --muted:#526079;
@@ -184,7 +184,7 @@
   <a class="skip-link" href="#main">跳到主要内容</a>
   <div class="prototype-banner">PROTOTYPE - 仅供枚举交互，非实现依据</div>
   <header class="app-header">
-    <a class="brand" href="web-task-workbench.html"><span class="brand-mark" aria-hidden="true">CM</span><span>cmbuyer</span></a>
+    <a class="brand" href="web-task-workbench.html" aria-label="采购服务原型工作台"><span class="brand-mark" aria-hidden="true">采</span><span>采购服务</span></a>
     <nav class="primary" aria-label="主导航"><a href="web-task-workbench.html" aria-current="page">采购任务</a><a href="web-task-create.html">建单直达页</a></nav>
     <span class="header-account">采购管理员 · caigou_admin</span>
   </header>