chore(release): 客户端班级账号收尾 + README/安装包产物更新

- 客户端设置页展示班级码与登录方式（班级账号 / 个人学生账号）
- 冒烟脚本复用已有班级凭据（现成的班级码 + 密码可直接登录时不再改密码，避免污染实例）
- README: 学生端班级账号章节、功能页面/API/验收/命令计数(verify:e2e 125)同步
- 安装包 README 默认账号补充班级码 G101/G102/G203 + 班级密码 123456

验收: pnpm verify:e2e 125/125, verify:web 18/18, verify:desktop 40/40,
      打包产物实测(portable.exe): 40/40, login=高一(1)班 classSession=true

packages/desktop-client/scripts/smoke.mjs

@@ -84,6 +84,17 @@ async function provisionClassAccount() {
     if (!target) return null;
 
     const code = target.code || `SMOKE${Math.floor(Math.random() * 9000 + 1000)}`;
+
+    // 若现有班级码 + 目标密码已经能登录，就直接复用，避免每次冒烟都改密码
+    if (target.code) {
+      const probe = await fetch(`${base}/auth/class-login`, {
+        method: 'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ code: target.code, password }),
+      });
+      if (probe.ok) return { code: target.code, password, className: target.name };
+    }
+
     const patchResponse = await fetch(`${base}/classes/${target.id}/class-account`, {
       method: 'PATCH',
       headers: authHeaders,

packages/desktop-client/src/renderer/views/SettingsView.vue

@@ -333,7 +333,12 @@ onMounted(async () => {
           <template #header><span>账号信息</span></template>
           <el-descriptions :column="1" border size="small">
             <el-descriptions-item label="姓名">{{ auth.user?.name ?? '-' }}</el-descriptions-item>
-            <el-descriptions-item label="用户名">{{ auth.user?.username ?? '-' }}</el-descriptions-item>
+            <el-descriptions-item :label="auth.isClassSession ? '班级码' : '用户名'">
+              {{ auth.user?.username ?? '-' }}
+            </el-descriptions-item>
+            <el-descriptions-item label="登录方式">
+              {{ auth.isClassSession ? '班级账号（本机代表全班）' : '个人学生账号' }}
+            </el-descriptions-item>
             <el-descriptions-item label="班级">{{ auth.user?.className ?? '未分班' }}</el-descriptions-item>
             <el-descriptions-item label="年级">{{ auth.user?.grade ?? '-' }}</el-descriptions-item>
           </el-descriptions>