feat(web): 题目页的「开启同步」换成「求助」

学生发起求助，状态与排队位置显示在按钮旁。
教师端入口不在题目页，所以对教师隐藏这个按钮。

顺带修正 handleHelpCancel：去掉 request.socket !== ws 的校验。
学生取消自己的求助，不管从他哪个标签页发起都合法——
getRequest(ws.data.userId) 已经把范围锁在这一个用户上了，
不是跨用户操作，不需要再比对是不是同一条连接。这层校验此前
会让「第二个标签页点取消」被服务端静默丢弃，前端却已经乐观
地把按钮变回「求助」，是一处 UI 说谎；现在两边状态一致。
handleCollabClose 里排队分支的 socket 归属校验不受影响，
那里的关闭事件是顺带触发的，仍然需要认出是不是本人这条连接。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01K1d8B3f4SXJwDvUY625eQd

apps/web/src/shared/components/SyncCodeEditor.vue

@@ -3,7 +3,6 @@ import { cpp } from "@codemirror/lang-cpp"
 import { python } from "@codemirror/lang-python"
 import { sql, SQLite } from "@codemirror/lang-sql"
 import { bracketMatching } from "@codemirror/language"
-import { EditorView } from "@codemirror/view"
 import { Codemirror } from "vue-codemirror"
 import {
   autocompletion,
@@ -15,20 +14,11 @@ import type { LANGUAGE } from "utils/types"
 import { oneDark } from "../themes/oneDark"
 import { smoothy } from "../themes/smoothy"
 import { styleTheme } from "shared/extensions/baseTheme"
-import { useCodeSync, SYNC_ERROR_CODES } from "../composables/sync"
-import { useBreakpoints } from "../composables/breakpoints"
 import { enhanceCompletion } from "shared/extensions/autocompletion"
 
 const isDark = useDark()
 
-interface EditorReadyPayload {
-  view: EditorView
-  state: any
-  container: HTMLElement
-}
-
 interface Props {
-  sync: boolean
   problem: string
   language?: LANGUAGE
   fontSize?: number
@@ -38,8 +28,6 @@ interface Props {
 }
 
 const {
-  sync,
-  problem,
   language = "Python3",
   fontSize = 20,
   height = "100%",
@@ -48,15 +36,6 @@ const {
 } = defineProps<Props>()
 const code = defineModel<string>("value")
 
-const emit = defineEmits<{
-  syncClosed: []
-  syncStatusChange: [
-    status: { otherUser?: { name: string; isSuperAdmin: boolean } },
-  ]
-}>()
-
-const { isDesktop } = useBreakpoints()
-
 const langExtension = computed((): Extension => {
   if (language === "SQL")
     return sql({ dialect: SQLite, upperCaseKeywords: true })
@@ -72,71 +51,8 @@ const extensions = computed(() => [
   autocompletion({
     override: [enhanceCompletion(language), completeAnyWord],
   }),
-  getInitialExtension(),
 ])
 
-const { startSync, stopSync, getInitialExtension } = useCodeSync()
-const editorView = ref<EditorView | null>(null)
-let cleanupSync: (() => void) | null = null
-
-const cleanupSyncResources = () => {
-  if (cleanupSync) {
-    cleanupSync()
-    cleanupSync = null
-  }
-  stopSync()
-}
-
-const initSync = async () => {
-  if (!editorView.value || !problem || !isDesktop.value) return
-
-  cleanupSyncResources()
-
-  cleanupSync = await startSync({
-    problemId: problem,
-    editorView: editorView.value as EditorView,
-    onStatusChange: (status) => {
-      // 处理需要断开同步的情况
-      if (
-        (status.errorCode === SYNC_ERROR_CODES.SUPER_ADMIN_LEFT ||
-          status.errorCode === SYNC_ERROR_CODES.MISSING_SUPER_ADMIN) &&
-        !status.connected
-      ) {
-        emit("syncClosed")
-      }
-      emit("syncStatusChange", { otherUser: status.otherUser })
-    },
-  })
-}
-
-const handleEditorReady = (payload: EditorReadyPayload) => {
-  editorView.value = payload.view as EditorView
-  if (sync) {
-    initSync()
-  }
-}
-
-watch(
-  () => sync,
-  (shouldSync) => {
-    if (shouldSync) {
-      initSync()
-    } else {
-      cleanupSyncResources()
-    }
-  },
-)
-
-watch(
-  () => problem,
-  (newProblem, oldProblem) => {
-    if (newProblem !== oldProblem && sync) {
-      initSync()
-    }
-  },
-)
-
-onUnmounted(cleanupSyncResources)
 </script>
 
 <template>
@@ -148,6 +64,5 @@ onUnmounted(cleanupSyncResources)
     :tab-size="4"
     :placeholder="placeholder"
     :style="{ height, fontSize: `${fontSize}px` }"
-    @ready="handleEditorReady"
   />
 </template>