feat(阶段4): 题目管理 / 比赛题目 / 比赛题⇄公开题互转

GET/POST          admin/problems
  GET/PUT/DELETE    admin/problems/:id
  POST              admin/problems/:id/make-public
  GET/POST          admin/contests/:contestId/problems
  POST              admin/contests/:contestId/problems/from-public

合并了旧后端拆开的两套路由：旧 admin/problem 与 admin/contest/problem 的
GET 详情、PUT、DELETE 都只按题目 id 取、比赛是从题目推导出来的，分开没有意义，
还逼前端多传一个它未必知道的 contestId。现在共用 /admin/problems/:id。

归属判断按旧后端的口径分开：**比赛题看比赛的创建者，公开题看题目自己的创建者**
（旧 ensure_created_by(problem.contest, user) vs ensure_created_by(problem, user)）。
一道比赛题的 created_by 可能是克隆时的操作人，跟谁有权改它没关系。
题号唯一性的作用域也跟着走：公开题在全部公开题里唯一，比赛题在本场比赛内唯一。

删题不删测试用例目录，与旧后端一致（它把 rmtree 注释掉了）：删错了还能从磁盘捞回来，
而误删的测试数据没有别处备份；孤儿目录另有清理入口。有提交记录的题目拒绝删除。

## SQL 题目前只能编辑、不能新建

新后端**没有 SQL 判题链路** —— 旧 judge/sql_runner.py（378 行）+ sql_dispatcher.py
（113 行）无对应实现，languages.ts 里也只有 C/C++/Java/Golang/JavaScript/Python3 六种。
题目页给学生看的表结构与期望结果（sql_display）要跑 SQLite 现算，算不出来就没法建题。

因此：新建 SQL 题返回 501 并说明原因；**编辑已有 SQL 题时原样保留 sqlDisplay 不动** ——
不动它比生成一个错的安全，它直接决定学生看到的期望结果。SQL 的前置校验
（必须是唯一语言、要有 sql_config、要有 SQL 标准答案）照旧执行。

实测：学生 403；缺样例/缺输入描述/SQL 混语言三条校验文案与旧后端一致；
题号重复 409、跨比赛题号互不影响；公开题加入比赛后计数归零且标签带过来；
比赛题转公开后 visible=false、contestId=null、重复转 409；删除级联正常。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/web/src/admin/api.ts

@@ -38,21 +38,13 @@ export async function getProblemList(
   contestID?: string,
   tagId?: number,
 ) {
-  const endpoint = !!contestID ? "admin/contest/problem" : "admin/problem"
-  const res = await http.get<{ results: AdminProblem[]; total: number }>(
-    endpoint,
-    {
-      params: {
-        paging: true,
-        offset,
-        limit,
-        keyword,
-        author,
-        contest_id: contestID,
-        tag_id: tagId,
-      },
-    },
-  )
+  const endpoint = contestID
+    ? `admin/contests/${contestID}/problems`
+    : "admin/problems"
+  const res = await legacyResponse<{
+    results: AdminProblem[]
+    total: number
+  }>(api2.get(endpoint, { params: { offset, limit, keyword, author, tagId } }))
   return {
     results: res.data.results.map(toProblemListItem),
     total: res.data.total,
@@ -60,15 +52,21 @@ export async function getProblemList(
 }
 
 export function deleteProblem(id: number) {
-  return http.delete("admin/problem", { params: { id } })
+  return api2.delete(`admin/problems/${id}`)
 }
 
+// 比赛题与公开题共用一条删除路由，比赛由后端从题目推导
 export function deleteContestProblem(id: number) {
-  return http.delete("admin/contest/problem", { params: { id } })
+  return api2.delete(`admin/problems/${id}`)
 }
 
 export function editProblem(problem: AdminProblem | BlankProblem) {
-  return http.put("admin/problem", problem)
+  return legacyResponse(
+    api2.put(
+      `admin/problems/${(problem as AdminProblem).id}`,
+      toProblemBody(problem),
+    ),
+  )
 }
 
 export function toggleProblemVisible(problemID: number) {
@@ -80,15 +78,20 @@ export function generateFlowchartFromPythonCode(python: string) {
 }
 
 export function editContestProblem(problem: AdminProblem | BlankProblem) {
-  return http.put("admin/contest/problem", problem)
+  return legacyResponse(
+    api2.put(
+      `admin/problems/${(problem as AdminProblem).id}`,
+      toProblemBody(problem),
+    ),
+  )
 }
 
 export function getProblem(id: string | number) {
-  return http.get<AdminProblem>("admin/problem", { params: { id } })
+  return legacyResponse<AdminProblem>(api2.get(`admin/problems/${id}`))
 }
 
 export function getContestProblem(id: number) {
-  return http.get("admin/contest/problem", { params: { id } })
+  return legacyResponse<AdminProblem>(api2.get(`admin/problems/${id}`))
 }
 
 // 标签管理
@@ -239,12 +242,49 @@ export function generateSQLTestcase(data: {
   return http.post<{ sql: string }>("admin/sql_test_case_ai_gen", data)
 }
 
+/** 组件里的题目对象是 snake_case，出站转成新后端要的 camelCase */
+function toProblemBody(problem: AdminProblem | BlankProblem) {
+  const p = problem as Record<string, any>
+  return {
+    _id: p._id,
+    title: p.title,
+    description: p.description,
+    inputDescription: p.input_description ?? "",
+    outputDescription: p.output_description ?? "",
+    samples: p.samples ?? [],
+    testCaseId: p.test_case_id,
+    testCaseScore: p.test_case_score ?? [],
+    timeLimit: p.time_limit,
+    memoryLimit: p.memory_limit,
+    languages: p.languages ?? [],
+    template: p.template ?? {},
+    visible: p.visible,
+    difficulty: p.difficulty,
+    tags: p.tags ?? [],
+    hint: p.hint ?? null,
+    source: p.source ?? null,
+    prompt: p.prompt ?? null,
+    answers: p.answers ?? [],
+    shareSubmission: p.share_submission ?? false,
+    allowFlowchart: p.allow_flowchart ?? false,
+    showFlowchart: p.show_flowchart ?? false,
+    mermaidCode: p.mermaid_code ?? null,
+    flowchartHint: p.flowchart_hint ?? null,
+    astRules: p.ast_rules ?? null,
+    sqlConfig: p.sql_config ?? null,
+  }
+}
+
 export function createProblem(problem: BlankProblem) {
-  return http.post("admin/problem", problem)
+  return legacyResponse(api2.post("admin/problems", toProblemBody(problem)))
 }
 
 export function createContestProblem(problem: BlankProblem) {
-  return http.post("admin/contest/problem", problem)
+  // contest_id 由 detail.vue 在提交前写进 problem 对象
+  const contestID = (problem as Record<string, any>).contest_id
+  return legacyResponse(
+    api2.post(`admin/contests/${contestID}/problems`, toProblemBody(problem)),
+  )
 }
 
 /** 组件里的比赛对象是 snake_case，出站转成新后端要的 camelCase */
@@ -289,11 +329,12 @@ export function addProblemForContest(
   problemID: number,
   displayID: string,
 ) {
-  return http.post("admin/contest/add_problem_from_public", {
-    contest_id: contestID,
-    problem_id: problemID,
-    display_id: displayID,
-  })
+  return legacyResponse(
+    api2.post(`admin/contests/${contestID}/problems/from-public`, {
+      problemId: problemID,
+      displayId: displayID,
+    }),
+  )
 }
 
 export function getWebsite() {
@@ -451,10 +492,9 @@ export function deleteExercise(id: number) {
 
 // 将竞赛题目转为公开题目
 export function makeProblemPublic(id: number, display_id: string) {
-  return http.post("admin/contest_problem/make_public", {
-    id,
-    display_id,
-  })
+  return legacyResponse(
+    api2.post(`admin/problems/${id}/make-public`, { displayId: display_id }),
+  )
 }
 
 // 比赛辅助检查