布置作业、提交与自动评分

- 作业：老师选实验、起点（界面已做好 / 空白工程）、截止时间、每项分值（自动评分项 + 老师评分项）；
  起点工程由设计器引擎从参考答案生成（去掉事件绑定和事件处理方法），布置时保存起点和评分规则快照
- 提交：后台排队评分（全站同时最多评 3 份、跑 6 个检查项），重启后继续评；评分中不能再交，截止后不能交
- 学生："我的作业"列表；实验页的作业模式（作业名、截止时间、提交、得分），评分结果弹出逐项显示
- 老师：班级管理页加"作业"标签页，布置、修改、删除作业，查看全班提交情况；改分值后重新算分
- 串口列表为空时提示在 Load 或 Click 事件里填充
- 测试：作业接口（可见范围、排队评分、部分得分、改分值、截止、删除）；10 个示例两种起点都能编译

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

web/src/teacher/AssignmentsPanel.vue

@@ -0,0 +1,111 @@
+<script setup lang="ts">
+// 一个班的作业列表：布置、修改、删除作业，查看提交情况。
+import { h, ref, watch } from 'vue'
+import { NButton, NDataTable, NEmpty, useDialog, useMessage, type DataTableColumns } from 'naive-ui'
+import type { Assignment } from '@iot/shared'
+import { api } from '../api'
+import AssignmentDialog from './AssignmentDialog.vue'
+import SubmissionsDialog from './SubmissionsDialog.vue'
+
+type Row = Assignment & { studentCount: number; submittedCount: number }
+
+const props = defineProps<{ classId: number }>()
+const message = useMessage()
+const dialog = useDialog()
+
+const rows = ref<Row[]>([])
+const editorOpen = ref(false)
+const editing = ref<Assignment | null>(null)
+const submissionsOpen = ref(false)
+const viewing = ref<Assignment | null>(null)
+
+async function load() {
+  rows.value = await api<Row[]>('GET', `/api/teacher/classes/${props.classId}/assignments`).catch((e: Error) => {
+    message.error(e.message)
+    return []
+  })
+}
+watch(() => props.classId, load, { immediate: true })
+
+function create() {
+  editing.value = null
+  editorOpen.value = true
+}
+
+function edit(row: Row) {
+  editing.value = row
+  editorOpen.value = true
+}
+
+function remove(row: Row) {
+  dialog.warning({
+    title: '删除作业',
+    content: `将删除"${row.title}"和全班的 ${row.submittedCount} 份提交，不能恢复。确定删除吗？`,
+    positiveText: '删除',
+    negativeText: '取消',
+    onPositiveClick: async () => {
+      await api('DELETE', `/api/teacher/assignments/${row.id}`).catch((e: Error) => message.error(e.message))
+      await load()
+    },
+  })
+}
+
+function showSubmissions(row: Row) {
+  viewing.value = row
+  submissionsOpen.value = true
+}
+
+const formatTime = (ms: number) =>
+  new Date(ms).toLocaleString('zh-CN', { month: 'numeric', day: 'numeric', hour: '2-digit', minute: '2-digit' })
+
+const columns: DataTableColumns<Row> = [
+  { title: '作业', key: 'title' },
+  { title: '起点', key: 'startMode', width: 110, render: (r) => (r.startMode === 'ui' ? '界面已做好' : '空白工程') },
+  { title: '截止时间', key: 'deadline', width: 130, render: (r) => (r.deadline ? formatTime(r.deadline) : '不限') },
+  {
+    title: '已提交',
+    key: 'submitted',
+    width: 120,
+    render: (r) => h(NButton, { text: true, type: 'primary', onClick: () => showSubmissions(r) }, () => `${r.submittedCount} / ${r.studentCount} 人`),
+  },
+  {
+    title: '操作',
+    key: 'actions',
+    width: 130,
+    render: (r) =>
+      h('div', { class: 'row-actions' }, [
+        h(NButton, { size: 'tiny', onClick: () => edit(r) }, () => '修改'),
+        h(NButton, { size: 'tiny', type: 'error', quaternary: true, onClick: () => remove(r) }, () => '删除'),
+      ]),
+  },
+]
+</script>
+
+<template>
+  <div class="panel">
+    <div class="head">
+      <NButton size="small" type="primary" @click="create">布置作业</NButton>
+    </div>
+    <NDataTable v-if="rows.length" :columns="columns" :data="rows" :row-key="(r: Row) => r.id" size="small" :bordered="false" />
+    <NEmpty v-else description="还没有布置作业" class="empty" />
+    <AssignmentDialog v-model:show="editorOpen" :class-id="classId" :editing="editing" @saved="load" />
+    <SubmissionsDialog v-model:show="submissionsOpen" :assignment="viewing" />
+  </div>
+</template>
+
+<style scoped>
+.head {
+  display: flex;
+  justify-content: flex-end;
+  margin-bottom: 8px;
+}
+
+.empty {
+  margin-top: 40px;
+}
+
+:deep(.row-actions) {
+  display: flex;
+  gap: 6px;
+}
+</style>