fix(frontend): report overall NaN + header card styling

- NaN root cause: report.scores is nested { overall, dimensions: {...} };
  the old code treated every value as a number, so Number({object}) → NaN.
  Now: dimScores from scores.dimensions, overall prefers scores.overall.
- Header summary cards restyled: icon + colored big number + responsive
  (xs=12 md=6), colored score (>0.8 green / 0.6-0.8 amber / else red).

frontend/web/src/components/intelligent_eval/EvalReport.tsx

@@ -1,8 +1,11 @@
 import { useEffect, useState } from 'react'
 import {
-  Button, Card, Col, Collapse, Empty, Row, Space, Spin, Statistic, Tag, message,
+  Button, Card, Col, Collapse, Empty, Row, Space, Spin, Tag, message,
 } from 'antd'
-import { ArrowLeftOutlined, DownloadOutlined } from '@ant-design/icons'
+import {
+  ArrowLeftOutlined, BulbOutlined, DownloadOutlined, MessageOutlined,
+  StarOutlined, WarningOutlined,
+} from '@ant-design/icons'
 import { Bar } from '@ant-design/charts'
 import ChatBubble from '../ChatBubble'
 import {
@@ -125,16 +128,28 @@ export default function EvalReport({ ev, onBack }: EvalReportProps) {
 
   const findings = [...(report?.findings ?? [])]
     .sort((a, b) => severityOf(a.severity).order - severityOf(b.severity).order)
-  const scores = Object.entries(report?.scores ?? {})
+  // report.scores 是嵌套结构：{ overall: number, dimensions: { 维度: 分 } }
-  const overall = scores.length > 0
+  // 只把 dimensions 的值当作数字维度，overall 单独取，避免 Number(对象) 产生 NaN。
-    ? (scores.reduce((sum, [, v]) => sum + Number(v), 0) / scores.length).toFixed(1)
+  const rawScores = report?.scores ?? {}
-    : null
+  const dimScores = Object.entries(rawScores.dimensions ?? {}).filter(
+    ([, v]) => typeof v === 'number',
+  )
+  const rawOverall = rawScores.overall
+  const overall = typeof rawOverall === 'number'
+    ? rawOverall.toFixed(1)
+    : dimScores.length > 0
+      ? (dimScores.reduce((sum, [, v]) => sum + Number(v), 0) / dimScores.length).toFixed(1)
+      : null
+  const overallNum = overall != null ? Number(overall) : null
+  const overallColor = overallNum == null ? colors.textMuted
+    : overallNum >= 0.8 ? '#52c41a'
+      : overallNum >= 0.6 ? colors.warning : '#ff4d4f'
   const sevCounts = findings.reduce((acc, f) => {
     acc[f.severity] = (acc[f.severity] ?? 0) + 1
     return acc
   }, {} as Record<string, number>)
 
-  const scoreData = scores.map(([dimension, score]) => ({ dimension, score: Number(score) }))
+  const scoreData = dimScores.map(([dimension, score]) => ({ dimension, score: Number(score) }))
   const scoreConfig = {
     data: scoreData,
     xField: 'dimension',
@@ -144,6 +159,19 @@ export default function EvalReport({ ev, onBack }: EvalReportProps) {
     color: colors.primary,
   }
 
+  const summaryCard: React.CSSProperties = {
+    display: 'flex', alignItems: 'center', gap: 10,
+    border: `1px solid ${colors.border}`,
+    borderRadius: 10, padding: '14px 16px', background: colors.bgContainer,
+    boxShadow: '0 1px 3px rgba(0,0,0,0.06)',
+    height: '100%',
+  }
+  const summaryIcon = (color: string): React.CSSProperties => ({
+    width: 42, height: 42, borderRadius: 10, flexShrink: 0,
+    display: 'flex', alignItems: 'center', justifyContent: 'center',
+    background: `${color}1a`, color, fontSize: 20,
+  })
+
   return (
     <div style={{ height: '100%', overflowY: 'auto', padding: 16 }}>
       <div style={{ display: 'flex', alignItems: 'center', gap: 8, marginBottom: 12 }}>
@@ -167,23 +195,53 @@ export default function EvalReport({ ev, onBack }: EvalReportProps) {
 
       {report && (
         <>
-          <Row gutter={[16, 16]} style={{ marginBottom: 16 }}>
+          <Row gutter={[12, 12]} style={{ marginBottom: 16 }}>
-            <Col span={6}>
+            <Col xs={12} md={6}>
-              <Card size="small"><Statistic title="综合评分" value={overall ?? '—'} /></Card>
+              <div style={summaryCard}>
-            </Col>
+                <div style={summaryIcon(overallColor)}><StarOutlined /></div>
-            <Col span={6}>
+                <div>
-              <Card size="small">
+                  <div style={{ fontSize: 12, color: colors.textMuted }}>综合评分</div>
-                <Statistic title="问题发现" value={findings.length} />
+                  <div style={{ fontSize: 26, fontWeight: 700, color: overallColor, lineHeight: 1.2 }}>
-                <div style={{ fontSize: 12, color: colors.textMuted }}>
+                    {overall ?? '—'}
-                  高 {sevCounts.high ?? 0} · 中 {sevCounts.medium ?? 0} · 低 {sevCounts.low ?? 0}
+                  </div>
                 </div>
-              </Card>
+              </div>
             </Col>
-            <Col span={6}>
+            <Col xs={12} md={6}>
-              <Card size="small"><Statistic title="亮点" value={report.highlights.length} /></Card>
+              <div style={summaryCard}>
+                <div style={summaryIcon('#ff4d4f')}><WarningOutlined /></div>
+                <div>
+                  <div style={{ fontSize: 12, color: colors.textMuted }}>问题发现</div>
+                  <div style={{ fontSize: 26, fontWeight: 700, color: colors.text, lineHeight: 1.2 }}>
+                    {findings.length}
+                  </div>
+                  <div style={{ fontSize: 12, color: colors.textMuted }}>
+                    高 {sevCounts.high ?? 0} · 中 {sevCounts.medium ?? 0} · 低 {sevCounts.low ?? 0}
+                  </div>
+                </div>
+              </div>
             </Col>
-            <Col span={6}>
+            <Col xs={12} md={6}>
-              <Card size="small"><Statistic title="会话数" value={ev.session_count} /></Card>
+              <div style={summaryCard}>
+                <div style={summaryIcon(colors.warning)}><BulbOutlined /></div>
+                <div>
+                  <div style={{ fontSize: 12, color: colors.textMuted }}>亮点</div>
+                  <div style={{ fontSize: 26, fontWeight: 700, color: colors.text, lineHeight: 1.2 }}>
+                    {report.highlights.length}
+                  </div>
+                </div>
+              </div>
+            </Col>
+            <Col xs={12} md={6}>
+              <div style={summaryCard}>
+                <div style={summaryIcon(colors.primary)}><MessageOutlined /></div>
+                <div>
+                  <div style={{ fontSize: 12, color: colors.textMuted }}>会话数</div>
+                  <div style={{ fontSize: 26, fontWeight: 700, color: colors.text, lineHeight: 1.2 }}>
+                    {ev.session_count}
+                  </div>
+                </div>
+              </div>
             </Col>
           </Row>