fix: 提示词链里的引导提问不算轮数，分类器固定结果、跳过过短输入

- 引导对话和 AI 对话存在同一个对话里，提示词链把它当成一轮“AI 对话”，显示“没有网页”。
  现在标成“引导”，淡化显示，不计入轮数，也不能选中（↑↓ 跳过）
- 分类器 temperature 设为 0：同一句提示词以前约两成会被打成不同层级
- 不到 4 个字的提问（“1”“，”等）不打层级，--force 重标时清掉旧标签

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

server/src/services/classifier.ts

@@ -13,6 +13,8 @@ const CLASSIFY_SYSTEM_PROMPT = `你是一个教育评估专家。根据布鲁姆
 
 只返回一个数字（1-6），不要解释。`
 
+const MIN_PROMPT_CHARS = 4
+
 const sleep = (ms: number) => new Promise((r) => setTimeout(r, ms))
 
 async function callLlm(content: string): Promise<number | null> {
@@ -23,7 +25,8 @@ async function callLlm(content: string): Promise<number | null> {
         { role: "system", content: CLASSIFY_SYSTEM_PROMPT },
         { role: "user", content },
       ],
-      { maxTokens: 10, timeoutMs: 30_000 },
+      // 同一句提示词要得到同一个层级
+      { maxTokens: 10, temperature: 0, timeoutMs: 30_000 },
     )
     const match = /[1-6]/.exec(text)
     if (!match) {
@@ -43,6 +46,11 @@ export async function classifyMessage(messageId: number): Promise<number | null>
     { id: messageId },
   )
   if (!msg) return null
+  // “1”“，”“可以”这类太短，判断不出层级；清掉以前打的标签（--force 重标时）
+  if ([...msg.content.trim()].length < MIN_PROMPT_CHARS) {
+    run(`UPDATE prompt_message SET prompt_level = NULL WHERE id = $id`, { id: messageId })
+    return null
+  }
   const level = await callLlm(msg.content)
   if (level !== null) {
     run(`UPDATE prompt_message SET prompt_level = $level WHERE id = $id`, {

server/src/services/llm.ts

@@ -63,6 +63,7 @@ interface CompletionOptions {
   model?: string
   stream: boolean
   maxTokens?: number
+  temperature?: number
   signal?: AbortSignal
   timeoutMs?: number
 }
@@ -82,6 +83,7 @@ function buildRequest(messages: ChatMessage[], opts: CompletionOptions) {
     stream: opts.stream,
   }
   if (opts.maxTokens) body.max_tokens = opts.maxTokens
+  if (opts.temperature !== undefined) body.temperature = opts.temperature
   const apiKey = ark ? config.arkApiKey : config.llmApiKey
   if (!apiKey) throw new Error("未配置模型接口密钥")
   const baseUrl = (ark ? config.arkBaseUrl : config.llmBaseUrl).replace(/\/$/, "")
@@ -203,12 +205,13 @@ export function streamGuidance(history: ChatMessage[], signal?: AbortSignal) {
 
 export async function complete(
   messages: ChatMessage[],
-  opts: { model?: string; maxTokens?: number; timeoutMs?: number } = {},
+  opts: { model?: string; maxTokens?: number; temperature?: number; timeoutMs?: number } = {},
 ): Promise<string> {
   const res = await buildRequest(messages, {
     model: opts.model ?? config.llmModel,
     stream: false,
     maxTokens: opts.maxTokens,
+    temperature: opts.temperature,
     timeoutMs: opts.timeoutMs,
   })
   await ensureOk(res)

server/tests/api.test.ts

@@ -646,3 +646,16 @@ describe("课堂总结", () => {
     expect(all.json.top_scored.map((t: any) => t.username)).toEqual(["weba2小李", "weba1小明"])
   })
 })
+
+describe("提示词分类", () => {
+  test("太短的提问不打层级，以前打的也清掉", async () => {
+    const { classifyMessage } = await import("../src/services/classifier")
+    const { createConversation, insertMessage } = await import("../src/services/prompt")
+    const conv = createConversation(makeUser("stu"), makeTask("T"))
+    const id = insertMessage({ conversation_id: conv, role: "user", content: " 1 " })
+    run(`UPDATE prompt_message SET prompt_level = 6 WHERE id = $id`, { id })
+    expect(await classifyMessage(id)).toBeNull()
+    const row = get<{ prompt_level: number | null }>(`SELECT prompt_level FROM prompt_message WHERE id = $id`, { id })
+    expect(row!.prompt_level).toBeNull()
+  })
+})