feat: 富文本消息类型支持 — Markdown/代码块安全渲染 + 审查解析器

添加 review_parser.go 从 LLM 输出中提取 Markdown 和代码块，创建独立
ReviewMessage 类型 (markdown/code/search_result)。前端新增安全 Markdown
渲染器 (HTML 转义优先)，代码块以深色背景+语言标签展示。Markdown/代码
类型禁止断句拆分，避免格式损坏。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/web/src/components/chat/MessageBubble.tsx

@@ -5,6 +5,7 @@ import { useChatStore } from '@/store/chatStore';
 import { useSpeechSynthesis } from '@/hooks/useSpeechSynthesis';
 import type { MessageAttachment, MultiMessageItem, StreamSegment, MessageDisplayType } from '@/types/chat';
 import { ImageLightbox } from './ImageLightbox';
+import { MarkdownRenderer } from './MarkdownRenderer';
 
 interface MessageBubbleProps {
   id: string;
@@ -16,6 +17,7 @@ interface MessageBubbleProps {
   multiMessages?: MultiMessageItem[];
   streamSegments?: StreamSegment[];
   msgType?: MessageDisplayType;
+  metadata?: Record<string, unknown>;
 }
 
 /**
@@ -152,12 +154,15 @@ export function MessageBubble({
   multiMessages,
   streamSegments,
   msgType,
+  metadata,
 }: MessageBubbleProps) {
   const isUser = role === 'user';
   const isAction = role === 'action' || msgType === 'action';
   const isThinking = msgType === 'thinking';
   const isToolProgress = msgType === 'tool_progress';
   const isSystemInfo = msgType === 'system_info';
+  const isMarkdown = msgType === 'markdown';
+  const isCode = msgType === 'code';
 
   // 动作消息使用独立的渲染方式
   if (isAction) {
@@ -195,6 +200,45 @@ export function MessageBubble({
     );
   }
 
+  // 代码块 — 独立渲染，深色背景 + 语言标签
+  if (isCode) {
+    const lang = (metadata?.language as string) || '';
+    return (
+      <div className="flex px-4 py-0.5 gap-2 items-start group animate-fadeIn">
+        <div className="w-8 flex-shrink-0" />
+        <div className="max-w-[85%] w-full my-1 rounded-xl overflow-hidden border border-gray-200 dark:border-gray-700 bg-gray-900 dark:bg-gray-950 shadow-sm">
+          {lang && (
+            <div className="flex items-center justify-between px-3 py-1.5 bg-gray-800 dark:bg-gray-900 border-b border-gray-700">
+              <span className="text-[10px] uppercase tracking-wider text-gray-400 font-mono">{lang}</span>
+            </div>
+          )}
+          <pre className="px-4 py-3 overflow-x-auto">
+            <code className="text-xs md:text-sm text-gray-100 font-mono leading-relaxed whitespace-pre">{content}</code>
+          </pre>
+        </div>
+        <p className="text-[10px] text-gray-400 flex-shrink-0 hidden md:block md:opacity-0 group-hover:opacity-100 transition-opacity">
+          {new Date(timestamp).toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' })}
+        </p>
+      </div>
+    );
+  }
+
+  // Markdown — 在昔涟气泡内使用 MarkdownRenderer
+  if (isMarkdown) {
+    const time = new Date(timestamp).toLocaleTimeString('zh-CN', { hour: '2-digit', minute: '2-digit' });
+    return (
+      <div className="flex px-4 py-2 gap-2 items-end group">
+        <CyreneAvatar size="sm" className="flex-shrink-0 mb-0.5" />
+        <div className="max-w-[75%] px-4 py-2.5 rounded-2xl text-sm leading-relaxed shadow-sm bg-white dark:bg-gray-800 text-gray-700 dark:text-gray-200 rounded-bl-md border border-pink-100 dark:border-pink-900">
+          <MarkdownRenderer content={content} />
+        </div>
+        <p className="text-[10px] text-gray-400 dark:text-gray-500 flex-shrink-0 mb-1 hidden md:block md:opacity-0 group-hover:opacity-100 transition-opacity duration-200">
+          {time}
+        </p>
+      </div>
+    );
+  }
+
   const [lightboxIndex, setLightboxIndex] = useState<number | null>(null);
   const time = new Date(timestamp).toLocaleTimeString('zh-CN', {
     hour: '2-digit',