fix: AI 对话和引导里的提问回复完后自动打层级

旧后端在消息保存后自动分类，改写成 Bun 时漏了：只有外部 AI 版本和手动提交带的提示词会分类，
学生在 AI 对话和引导里发的提问都没有层级。现在回复存库后在后台分类（失败或断开的提问不分类）。

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

server/src/ws.ts

@@ -15,6 +15,7 @@ import {
   userFacingError,
   type ChatMessage,
 } from "./services/llm"
+import { classifyMessage, inBackground } from "./services/classifier"
 
 type Kind = "prompt" | "guidance"
 
@@ -116,11 +117,12 @@ async function handlePrompt(ws: WS, data: any) {
   const model = String(data.model ?? "")
   if (!prompt) return
 
-  ws.data.pendingUserMessageId = insertMessage({
+  const userMessageId = insertMessage({
     conversation_id: ws.data.conversationId,
     role: "user",
     content: prompt,
   })
+  ws.data.pendingUserMessageId = userMessageId
   try {
     const history: ChatMessage[] = conversationHistory(ws.data.conversationId).map((m) => ({
       role: m.role as ChatMessage["role"],
@@ -146,6 +148,8 @@ async function handlePrompt(ws: WS, data: any) {
       code_css: code.css,
       code_js: code.js,
     })
+    // 有了回复，这条提问才留下来；在后台打 L1–L6 层级
+    inBackground(classifyMessage(userMessageId))
     ws.data.pendingUserMessageId = null
     send(ws, { type: "complete", code, message_id: messageId })
   } finally {
@@ -157,12 +161,13 @@ async function handleGuidance(ws: WS, data: any) {
   const prompt = String(data.content ?? "").trim()
   if (!prompt) return
 
-  ws.data.pendingUserMessageId = insertMessage({
+  const userMessageId = insertMessage({
     conversation_id: ws.data.conversationId,
     role: "user",
     content: prompt,
     source: "guidance",
   })
+  ws.data.pendingUserMessageId = userMessageId
   ws.data.guidanceHistory.push({ role: "user", content: prompt })
   try {
     let full: string
@@ -185,6 +190,7 @@ async function handleGuidance(ws: WS, data: any) {
       content: clean,
       source: "guidance",
     })
+    inBackground(classifyMessage(userMessageId))
     ws.data.pendingUserMessageId = null
     send(ws, { type: "complete", message_id: messageId, is_ready: isReady })
   } finally {

server/tests/ws.test.ts

@@ -8,12 +8,18 @@ import { client, freshDb, makeTask, makeUser } from "./helpers"
 
 // 假的模型接口：每段之间停一下，方便测试中途断开
 const PIECES = ["好的", "```html\n<p>hi</p>\n```"]
-// 最近一次发给模型的请求
+// 最近一次发给模型的请求；分类（非流式）单独记，固定回“3”
 let lastRequest: any = null
+let lastClassify: any = null
 const llm = Bun.serve({
   port: 0,
   async fetch(req) {
-    lastRequest = await req.json()
+    const body: any = await req.json()
+    if (!body.stream) {
+      lastClassify = body
+      return Response.json({ choices: [{ message: { content: "3" } }] })
+    }
+    lastRequest = body
     const enc = new TextEncoder()
     const stream = new ReadableStream({
       async start(ctrl) {
@@ -106,6 +112,19 @@ describe("WebSocket 代码生成", () => {
     c.ws.close()
   })
 
+  test("回复完后在后台给提问打层级", async () => {
+    const { task, token } = await setup()
+    const c = (await connect(`/ws/prompt/${task}/?token=${token}`))!
+    await c.next("init")
+    c.ws.send(JSON.stringify({ type: "message", content: "做个页面" }))
+    await c.next("complete")
+    const level = () => all(`SELECT prompt_level FROM prompt_message WHERE role = 'user'`)[0]?.prompt_level
+    for (let i = 0; i < 50 && level() == null; i++) await Bun.sleep(20)
+    expect(level()).toBe(3)
+    expect(lastClassify.thinking).toEqual({ type: "disabled" })
+    c.ws.close()
+  })
+
   test("AI 回复中再发消息会被拒绝", async () => {
     const { task, token } = await setup()
     const c = (await connect(`/ws/prompt/${task}/?token=${token}`))!