feat(提交列表): 老师也能重新判题；列表能按班级、一次按几道题筛，还带「通过几个测试点」

- 重新判题从只放超管改成老师及以上：前端一直给老师亮着按钮，点了只会「权限不足」
- /submissions、/flowcharts 加 className（user.class_name 精确匹配），题号可以一次填几道
- 列表每行带 caseSummary，口径和详情一致，在库里数完只回两个数
- 新增 GET /classroom/lesson：提交列表「这节课」按钮用，班级和题的取法同课堂看板

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

apps/api/src/routes/classroom.ts

@@ -5,6 +5,7 @@ import {
   type ClassActivity,
   type ClassBoard,
   type ClassBoardStudent,
+  type ClassLesson,
   type ClassActivityProblem,
   type ClassComparison,
   type ClassComparisonResponse,
@@ -671,6 +672,22 @@ classroomRoutes.get("/classroom/board", requireTeacher, async (c) => {
  * 有对不上的题号就整个拒掉并点名是哪几个，免得存下半张单子老师还不知道。空数组 = 清掉，
  * 学生那边退回推断。
  */
+classroomRoutes.get("/classroom/lesson", requireTeacher, async (c) => {
+  const className = c.req.query("className")?.trim() || (await suggestActiveClass())
+  if (!className)
+    return success(c, { className: null, source: null, problems: [] } satisfies ClassLesson)
+  // 和看板一样只回看今天：「这节课」不该冒出昨天的题
+  const lesson = await classLessonProblems(className, 1)
+  return success(c, {
+    className,
+    source: lesson.source,
+    problems: lesson.problems.map((problem) => ({
+      problemDisplayId: problem.displayId,
+      title: problem.title,
+    })),
+  } satisfies ClassLesson)
+})
+
 classroomRoutes.put("/classroom/lesson", requireTeacher, async (c) => {
   const parsed = await parseBody(c, classLessonRequestSchema, "题号格式不对")
   if (!parsed.success) return parsed.response