feat(布置作业): 能布置「画流程图」「先画再写」，看板分清卡在画图还是写代码

布置时多一个「做什么」：写代码 / 先画再写 / 画流程图（只能选打开了画流程图的题）。
- 先画再写：一道题图画到 A/S、代码也交对才算做完；学生画一道写一道、全画完再写都行，
  打开题目自动停在该做的那一步（图没画对停画布，画对了换到布置的语言）
- 也能分开布置：先一节画流程图，看板上「用这几道题写代码」再开一节；学生那边把今天
  几节课的要求合起来，还没画完的照样看得到要画
- 看板格子是一条进度：图 1/6 → 空心「图 ✓」→ 代码 ✗ → ✓，先写代码没画图的写「缺图」；
  卡在画图上的点开讲那张图（要改的框标红 + AI 的哪里错/怎么改），按走对几组归堆
- 写代码的课不再拿画对的流程图顶替做完；数据统计里画流程图的课数流程图提交

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

apps/web/src/admin/lesson/components/LessonEditModal.vue

@@ -1,6 +1,6 @@
 <script setup lang="ts">
 import { Icon } from '@iconify/vue'
-import type { AdminLesson, LessonLanguage } from '@oj2/contract'
+import { LESSON_MODE_LABEL, lessonNeeds, type AdminLesson, type LessonLanguage, type LessonMode } from '@oj2/contract'
 import ProblemPicker from 'oj/classroom/components/ProblemPicker.vue'
 import { useConfigStore } from 'shared/store/config'
 import { errorMessage } from 'utils/api'
@@ -24,12 +24,16 @@ const configStore = useConfigStore()
 
 const LESSON_LANGUAGES: LessonLanguage[] = ['Python', 'C', 'C++', 'SQL']
 const languageOptions = LESSON_LANGUAGES.map((value) => ({ label: LANGUAGE_SHOW_VALUE[value], value }))
+const modeOptions = (['code', 'both', 'flowchart'] as const).map((value) => ({ label: LESSON_MODE_LABEL[value], value }))
 const classOptions = computed(() => groupClassOptions(configStore.config?.classList ?? []))
 
 const className = ref<string | null>(null)
 const day = ref<string | null>(null)
 const time = ref<string | null>(null)
 const language = ref<LessonLanguage>('Python')
+/** 做什么：画流程图不用选语言（存成 null） */
+const mode = ref<LessonMode>('code')
+const needsCode = computed(() => lessonNeeds(mode.value).code)
 const idsInput = ref('')
 const saving = ref(false)
 
@@ -42,6 +46,7 @@ watch(show, (open) => {
   day.value = lesson?.day ?? parseTime(now, 'YYYY-MM-DD')
   time.value = parseTime(lesson?.createdAt ?? now, 'HH:mm')
   language.value = lesson?.language ?? 'Python'
+  mode.value = lesson?.mode ?? 'code'
   idsInput.value = lesson?.problems.map((p) => p.problemDisplayId).join(' ') ?? ''
 })
 
@@ -71,7 +76,8 @@ async function save() {
     className: className.value!,
     day: day.value!,
     time: time.value!,
-    language: language.value,
+    language: needsCode.value ? language.value : null,
+    mode: mode.value,
     problemDisplayIds: inputIds(),
   }
   try {
@@ -90,7 +96,7 @@ async function save() {
 
 <template>
   <n-modal v-model:show="show" preset="card" :title="lesson ? '改这一节' : '补一节'" :bordered="false" :style="{ width: 'min(520px, calc(100vw - 32px))' }">
-    <n-form label-placement="left" label-width="56">
+    <n-form label-placement="left" label-width="64">
       <n-form-item label="班级">
         <n-select v-model:value="className" :options="classOptions" filterable placeholder="选班级" />
       </n-form-item>
@@ -100,8 +106,11 @@ async function save() {
           <n-time-picker v-model:formatted-value="time" value-format="HH:mm" format="HH:mm" class="time" />
         </div>
       </n-form-item>
-      <n-form-item label="语言">
-        <n-select v-model:value="language" :options="languageOptions" class="lang" />
+      <n-form-item label="做什么">
+        <div class="when">
+          <n-select v-model:value="mode" :options="modeOptions" class="lang" />
+          <n-select v-if="needsCode" v-model:value="language" :options="languageOptions" aria-label="用什么语言写" class="lang" />
+        </div>
       </n-form-item>
       <n-form-item label="题目">
         <div class="ids">
@@ -119,7 +128,15 @@ async function save() {
         <n-button type="primary" :disabled="!ready" :loading="saving" @click="save">{{ lesson ? '保存' : '补上' }}</n-button>
       </div>
     </template>
-    <ProblemPicker v-model:show="picking" v-model:language="language" :initial="pickerInitial" :saving="false" mode="pick" @confirm="picked" />
+    <ProblemPicker
+      v-model:show="picking"
+      v-model:language="language"
+      v-model:lesson-mode="mode"
+      :initial="pickerInitial"
+      :saving="false"
+      mode="pick"
+      @confirm="picked"
+    />
   </n-modal>
 </template>
 

apps/web/src/admin/lesson/list.vue

@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import type { AdminLesson, AdminLessonList } from '@oj2/contract'
+import { LESSON_MODE_LABEL, type AdminLesson, type AdminLessonList } from '@oj2/contract'
 import { useRouteQuery } from '@vueuse/router'
 import PageHeader from 'admin/components/PageHeader.vue'
 import { NButton, NPopconfirm, NTooltip, useThemeVars } from 'naive-ui'
@@ -133,16 +133,17 @@ function renderActions(lesson: AdminLesson) {
   ])
 }
 
+/** 「画流程图」「先画再写 · C语言」「C语言」：写代码是默认的，不写出来 */
+function wayText(lesson: AdminLesson) {
+  return [lesson.mode !== 'code' ? LESSON_MODE_LABEL[lesson.mode] : '', lesson.language ? LANGUAGE_SHOW_VALUE[lesson.language] : ''].filter(Boolean).join(' · ')
+}
+
 /** 手机上一节课一张卡：日子 · 时刻 · 班级一行，题号一行，老师 · 语言 · 做完一行小字，操作一行 */
 function renderMobileCard(lesson: AdminLesson) {
   return h('div', { class: 'm-card' }, [
     h('div', { class: 'm-head' }, `${dayText(lesson.day)} ${parseTime(lesson.createdAt, 'HH:mm')} · ${classLabel(lesson.className)}`),
     renderProblems(lesson),
-    h(
-      'div',
-      { class: 'm-meta' },
-      [lesson.createdBy, lesson.language ? LANGUAGE_SHOW_VALUE[lesson.language] : null, `做完 ${renderDone(lesson)}`].filter(Boolean).join(' · '),
-    ),
+    h('div', { class: 'm-meta' }, [lesson.createdBy, wayText(lesson), `做完 ${renderDone(lesson)}`].filter(Boolean).join(' · ')),
     renderActions(lesson),
   ])
 }
@@ -152,7 +153,7 @@ const desktopColumns: DataTableColumn<AdminLesson>[] = [
   { title: '布置', key: 'createdAt', width: 70, render: (row) => parseTime(row.createdAt, 'HH:mm') },
   { title: '班级', key: 'className', width: 130, render: (row) => classLabel(row.className) },
   { title: '老师', key: 'createdBy', width: 90 },
-  { title: '语言', key: 'language', width: 80, render: (row) => (row.language ? LANGUAGE_SHOW_VALUE[row.language] : '—') },
+  { title: '做什么', key: 'language', width: 120, render: (row) => wayText(row) || '—' },
   { title: '题目', key: 'problems', width: 300, render: renderProblems },
   { title: '做完 / 全班', key: 'doneCount', width: 100, render: renderDone },
   { title: '', key: 'actions', render: renderActions },