fix(exams): fix duplicate React keys and composite question marking

- Fix parseOptions: deduplicate option ids within a single question to
  avoid multiple "A" keys when a question contains multiple lists
- Fix ExamPreview: use composite keys (questionId-optId, questionId-sub-id)
  to ensure global uniqueness across questions
- Fix selection-toolbar: when wrapInQuestion fails inside isolating nodes
  (e.g. composite question block), fall back to insertQuestion instead of
  silently doing nothing

src/modules/exams/components/exam-rich-form.tsx

@@ -411,7 +411,7 @@ function ExamPreview({ structure }: { structure: EditorDoc }) {
           <div className="space-y-1.5 pl-8 mb-2">
             {question.content.options.map((opt) => (
               <div
-                key={opt.id}
+                key={`${question.id}-${opt.id}`}
                 className="text-sm text-foreground/80 flex gap-2"
               >
                 <span className="font-medium min-w-[20px]">{opt.id}.</span>
@@ -424,7 +424,7 @@ function ExamPreview({ structure }: { structure: EditorDoc }) {
         {isComposite && question.content.subQuestions && question.content.subQuestions.length > 0 && (
           <div className="mt-3 ml-4 space-y-3 border-l-2 border-primary/30 pl-4">
             {question.content.subQuestions.map((sub, idx) => (
-              <div key={sub.id} className="text-sm">
+              <div key={`${question.id}-sub-${sub.id}`} className="text-sm">
                 <div className="flex items-center gap-2 mb-1">
                   <span className="font-medium text-foreground/80">
                     ({idx + 1})

src/modules/exams/editor/editor-to-structure.ts

@@ -55,17 +55,18 @@ const parseOptions = (
   nodes: JSONContent[]
 ): Array<{ id: string; text: string; isCorrect?: boolean }> => {
   const options: Array<{ id: string; text: string; isCorrect?: boolean }> = []
+  const seenIds = new Set<string>()
   for (const n of nodes) {
     if (n.type === "orderedList" || n.type === "bulletList") {
       if (Array.isArray(n.content)) {
         n.content.forEach((item, idx) => {
           const text = extractText(item).trim()
           const match = text.match(/^([A-Z])[.、)]\s*(.+)$/)
-          if (match) {
+          const id = match ? match[1]! : String.fromCharCode(65 + idx)
-            options.push({ id: match[1]!, text: match[2]! })
+          // 同一题目内选项 id 去重,避免多个列表合并后出现重复 "A"
-          } else {
+          if (seenIds.has(id)) return
-            options.push({ id: String.fromCharCode(65 + idx), text })
+          seenIds.add(id)
-          }
+          options.push({ id, text: match ? match[2]! : text })
         })
       }
     }

src/modules/exams/editor/selection-toolbar.tsx

@@ -94,12 +94,36 @@ export function SelectionToolbar({
       // 即使不在块内也允许显示(可标记为题目/分组)
       void inBlock
 
+      // 使用浏览器原生选区的可见矩形(相对视口),避免长文本选区起点
+      // 在视口外时 coordsAtPos 返回负坐标导致工具栏跑到页面顶部
+      const domSelection = window.getSelection()
+      let top: number
+      let left: number
+
+      if (domSelection && domSelection.rangeCount > 0) {
+        const rect = domSelection.getRangeAt(0).getBoundingClientRect()
+        // 选区不可见(滚动出视口)时 rect 为空矩形,此时不显示工具栏
+        if (rect.width === 0 && rect.height === 0) {
+          setCoords(null)
+          setHasSelection(false)
+          return
+        }
+        top = rect.top - 44 // 浮在选区上方
+        left = rect.left + rect.width / 2
+      } else {
+        // 降级:使用 ProseMirror 的 coordsAtPos
         const view = editor.view
         const start = view.coordsAtPos(from)
         const end = view.coordsAtPos(to)
-      const top = Math.min(start.top, end.top) - 44 // 浮在选区上方
+        top = Math.min(start.top, end.top) - 44
-      const left = (start.left + end.right) / 2
+        left = (start.left + end.right) / 2
-      setCoords({ top, left })
+      }
+
+      // 限制在视口内,避免超出顶部或左右边界
+      const clampedTop = Math.max(8, Math.min(top, window.innerHeight - 60))
+      const clampedLeft = Math.max(120, Math.min(left, window.innerWidth - 120))
+
+      setCoords({ top: clampedTop, left: clampedLeft })
       setHasSelection(true)
     }
 
@@ -128,7 +152,12 @@ export function SelectionToolbar({
     const chain = editor.chain().focus()
     if (hasTextSelection) {
       // 选中文本时:包裹为题目块
-      chain.wrapInQuestion({ type, score: type === "composite" ? 5 : 2 }).run()
+      // 注意:在 isolating 节点(如复合题)内,wrapIn 可能失败,
+      // 此时降级为插入空题目块
+      const success = chain.wrapInQuestion({ type, score: type === "composite" ? 5 : 2 }).run()
+      if (!success) {
+        chain.insertQuestion({ type, score: type === "composite" ? 5 : 2 }).run()
+      }
     } else {
       // 未选中文本时:插入空题目块
       chain.insertQuestion({ type, score: type === "composite" ? 5 : 2 }).run()