复盘统计改为分色堆叠柱状图，替代节点树图。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/components/ExamReviewPanel.tsx

@@ -3,7 +3,7 @@ import { useEffect, useMemo, useState } from 'react'
 import { examApi } from '../api/client'
 import type { Exam, ReviewStatus } from '../types'
 import { EXAM_TYPE_LABELS, REVIEW_STATUS_OPTIONS } from '../types'
-import ReviewTreeChart from './ReviewTreeChart'
+import ReviewBarChart from './ReviewBarChart'
 
 function apiErrorMessage(err: unknown, fallback: string): string {
   if (err && typeof err === 'object' && 'response' in err) {
@@ -147,7 +147,7 @@ export default function ExamReviewPanel({ exams, onRefresh }: Props) {
                 </>
               )}
               <Typography.Text strong>复盘统计</Typography.Text>
-              <ReviewTreeChart exams={exams} />
+              <ReviewBarChart exams={exams} />
             </Space>
           ),
         },

frontend/src/components/ReviewBarChart.tsx

@@ -0,0 +1,112 @@
+import ReactECharts from 'echarts-for-react'
+import type { Exam, ReviewStatus } from '../types'
+import { REVIEW_STATUS_LABELS } from '../types'
+
+interface Props {
+  exams: Exam[]
+}
+
+const STATUS_ORDER: ReviewStatus[] = ['careless', 'unknown', 'nervous', 'normal']
+
+const STATUS_COLORS: Record<ReviewStatus, string> = {
+  careless: '#fa8c16',
+  unknown: '#ff4d4f',
+  nervous: '#722ed1',
+  normal: '#52c41a',
+}
+
+function buildChartData(exams: Exam[]) {
+  const subjectSet = new Set<string>()
+  const counts: Record<ReviewStatus, Record<string, number>> = {
+    careless: {},
+    unknown: {},
+    nervous: {},
+    normal: {},
+  }
+
+  for (const exam of exams) {
+    for (const score of exam.scores) {
+      const subjectName = score.subject_name || `科目${score.subject_id}`
+      subjectSet.add(subjectName)
+      for (const status of score.review_statuses || []) {
+        counts[status][subjectName] = (counts[status][subjectName] || 0) + 1
+      }
+    }
+  }
+
+  const subjects = Array.from(subjectSet).sort((a, b) => a.localeCompare(b, 'zh-CN'))
+  return { subjects, counts }
+}
+
+export default function ReviewBarChart({ exams }: Props) {
+  const hasData = STATUS_ORDER.some((status) =>
+    exams.some((exam) =>
+      exam.scores.some((score) => (score.review_statuses || []).includes(status)),
+    ),
+  )
+
+  if (!hasData) {
+    return (
+      <div style={{ textAlign: 'center', padding: 32, color: '#999' }}>
+        暂无复盘数据，请在录入成绩或下方复盘中填写考试状态
+      </div>
+    )
+  }
+
+  const { subjects, counts } = buildChartData(exams)
+
+  const option = {
+    title: {
+      text: '各科考试状态统计',
+      left: 'center',
+      textStyle: { fontSize: 15, fontWeight: 500 },
+    },
+    tooltip: {
+      trigger: 'axis',
+      axisPointer: { type: 'shadow' },
+      formatter: (params: Array<{ seriesName: string; value: number; marker: string }>) => {
+        const rows = params.filter((p) => p.value > 0)
+        if (!rows.length) return ''
+        const total = rows.reduce((sum, p) => sum + p.value, 0)
+        return (
+          rows.map((p) => `${p.marker}${p.seriesName}: ${p.value} 次`).join('<br/>') +
+          `<br/><strong>合计: ${total} 次</strong>`
+        )
+      },
+    },
+    legend: {
+      bottom: 0,
+      data: STATUS_ORDER.map((s) => REVIEW_STATUS_LABELS[s]),
+    },
+    grid: { left: 48, right: 24, top: 48, bottom: 56 },
+    xAxis: {
+      type: 'category',
+      data: subjects,
+      axisLabel: { interval: 0, rotate: subjects.length > 6 ? 30 : 0 },
+    },
+    yAxis: {
+      type: 'value',
+      name: '次数',
+      minInterval: 1,
+      splitLine: { lineStyle: { type: 'dashed' } },
+    },
+    series: STATUS_ORDER.map((status) => ({
+      name: REVIEW_STATUS_LABELS[status],
+      type: 'bar',
+      stack: 'review',
+      barMaxWidth: 48,
+      emphasis: { focus: 'series' },
+      itemStyle: { color: STATUS_COLORS[status], borderRadius: [2, 2, 0, 0] },
+      data: subjects.map((subject) => counts[status][subject] || 0),
+    })),
+  }
+
+  return (
+    <div>
+      <ReactECharts option={option} style={{ height: 360, width: '100%' }} notMerge />
+      <p style={{ color: '#888', fontSize: 12, marginTop: 8 }}>
+        柱状图按科目展示各状态次数（分色堆叠）；同一科可多选状态，分别计数
+      </p>
+    </div>
+  )
+}