refactor(frontend): reuse ChatBubble for exploration drill-down

The drawer hand-rolled chat bubbles duplicating ChatBubble's shape.
Add a mirrored layout prop (virtual user left, target right) and reuse
the shared component.

frontend/web/src/components/ChatBubble.tsx

@@ -7,9 +7,11 @@ interface ChatBubbleProps {
   content: ReactNode
   meta?: ReactNode
   pending?: boolean
+  /** 镜像布局：探索下钻里虚拟用户居左、被评对象居右（与常规聊天相反） */
+  mirrored?: boolean
 }
 
-export default function ChatBubble({ role, content, meta, pending }: ChatBubbleProps) {
+export default function ChatBubble({ role, content, meta, pending, mirrored }: ChatBubbleProps) {
   const isUser = role === 'user'
   const isAgent = role === 'agent'
   const isSystem = role === 'system'
@@ -17,8 +19,9 @@ export default function ChatBubble({ role, content, meta, pending }: ChatBubbleP
   const bg = isUser ? colors.chatUser : isAgent ? colors.chatAgent : colors.chatSystemError
   const border = isSystem ? '#ffccc7' : 'transparent'
   const textColor = isSystem ? '#cf1322' : colors.text
-  const align = isUser ? 'flex-end' : 'flex-start'
-  const radius = isUser ? '10px 10px 2px 10px' : '10px 10px 10px 2px'
+  const alignRight = isSystem ? false : isUser ? !mirrored : !!mirrored
+  const align = alignRight ? 'flex-end' : 'flex-start'
+  const radius = alignRight ? '10px 10px 2px 10px' : '10px 10px 10px 2px'
 
   const icon = isUser
     ? <UserOutlined style={{ color: colors.primary }} />
@@ -29,7 +32,7 @@ export default function ChatBubble({ role, content, meta, pending }: ChatBubbleP
 
   return (
     <div style={{ display: 'flex', justifyContent: align, marginBottom: 6 }}>
-      <div style={{ maxWidth: '82%', display: 'flex', flexDirection: 'column', alignItems: isUser ? 'flex-end' : 'flex-start', gap: 2 }}>
+      <div style={{ maxWidth: '82%', display: 'flex', flexDirection: 'column', alignItems: alignRight ? 'flex-end' : 'flex-start', gap: 2 }}>
         <div style={{ display: 'flex', gap: 4, alignItems: 'center', fontSize: 11, color: colors.textMuted }}>
           {!isUser && icon}
           <span>{label}</span>

frontend/web/src/components/ExplorationSection.tsx

@@ -1,6 +1,6 @@
 import { useEffect, useState } from 'react'
 import { Collapse, Empty, Space, Spin, Tag } from 'antd'
-import { UserOutlined, RobotOutlined } from '@ant-design/icons'
+import ChatBubble from './ChatBubble'
 import {
   explorationApi,
   type ExplorationMessage,
@@ -78,33 +78,15 @@ function SessionDetail({ session, messages }: {
         <Empty description="暂无对话记录" image={Empty.PRESENTED_IMAGE_SIMPLE} />
       )}
       {messages && messages.map((m) => (
-        <div
+        <ChatBubble
           key={m.id}
-          style={{ display: 'flex', justifyContent: m.role === 'user' ? 'flex-start' : 'flex-end', marginBottom: 8 }}
-        >
-          {m.role === 'user' ? (
-            <div style={{
-              background: colors.chatUser, padding: '8px 14px',
-              borderRadius: '12px 12px 12px 2px', maxWidth: '70%',
-              fontSize: 13, lineHeight: 1.6,
-            }}>
-              <UserOutlined style={{ marginRight: 6, color: '#1677ff' }} />
-              {m.content}
-            </div>
-          ) : (
-            <div style={{
-              background: colors.chatAgent, padding: '8px 14px',
-              borderRadius: '12px 12px 2px 12px', maxWidth: '70%',
-              fontSize: 13, lineHeight: 1.6,
-            }}>
-              <RobotOutlined style={{ marginRight: 6, color: '#52c41a' }} />
-              {m.content}
-              {m.latency_ms != null && (
-                <span style={{ color: colors.textMuted, fontSize: 11, marginLeft: 8 }}>{m.latency_ms}ms</span>
-              )}
-            </div>
-          )}
-        </div>
+          role={m.role === 'user' ? 'user' : 'agent'}
+          mirrored
+          content={m.content}
+          meta={m.role !== 'user' && m.latency_ms != null ? (
+            <span style={{ color: colors.textMuted, fontSize: 11 }}>{m.latency_ms}ms</span>
+          ) : undefined}
+        />
       ))}
 
       {experience && (