feat: add Markdown rendering to text segments

- Add react-markdown + remark-gfm for GFM-compatible markdown rendering
- Create MarkdownRenderer component with custom Tailwind-styled elements
- Update TextSegmentView to render markdown instead of plain text
- Update LongTextView to render markdown when expanded
- Fix Lucide icon type in DocumentCard

.gitignore

@@ -1,3 +1,4 @@
 node_modules/
 dist/
 .DS_Store
+*.tsbuildinfo

package.json

@@ -12,7 +12,9 @@
   "dependencies": {
     "lucide-react": "^0.400.0",
     "react": "^18.3.1",
-    "react-dom": "^18.3.1"
+    "react-dom": "^18.3.1",
+    "react-markdown": "^10.1.0",
+    "remark-gfm": "^4.0.1"
   },
   "devDependencies": {
     "@types/react": "^18.3.3",

src/components/MarkdownRenderer.tsx

@@ -0,0 +1,167 @@
+import ReactMarkdown from 'react-markdown'
+import remarkGfm from 'remark-gfm'
+import type { Components } from 'react-markdown'
+
+/**
+ * Shared markdown renderer that converts markdown to styled HTML.
+ * Used by TextSegmentView, LongTextView, and any other component
+ * that needs to render user/assistant markdown content.
+ *
+ * Styling principle: all elements fit within a chat bubble context —
+ * compact spacing, readable sizes, no oversized headings.
+ */
+const components: Components = {
+  // --- Block elements ---
+  h1: ({ children, ...props }) => (
+    <h1 className="text-base font-bold text-gray-900 mt-3 mb-1.5 first:mt-0" {...props}>
+      {children}
+    </h1>
+  ),
+  h2: ({ children, ...props }) => (
+    <h2 className="text-sm font-bold text-gray-900 mt-2.5 mb-1 first:mt-0" {...props}>
+      {children}
+    </h2>
+  ),
+  h3: ({ children, ...props }) => (
+    <h3 className="text-sm font-semibold text-gray-800 mt-2 mb-1 first:mt-0" {...props}>
+      {children}
+    </h3>
+  ),
+  h4: ({ children, ...props }) => (
+    <h4 className="text-xs font-semibold text-gray-800 mt-1.5 mb-0.5" {...props}>
+      {children}
+    </h4>
+  ),
+  p: ({ children, ...props }) => (
+    <p className="text-gray-800 leading-relaxed mb-1.5 last:mb-0" {...props}>
+      {children}
+    </p>
+  ),
+
+  // --- Inline elements ---
+  strong: ({ children, ...props }) => (
+    <strong className="font-semibold text-gray-900" {...props}>
+      {children}
+    </strong>
+  ),
+  em: ({ children, ...props }) => (
+    <em className="italic text-gray-700" {...props}>
+      {children}
+    </em>
+  ),
+  a: ({ children, href, ...props }) => (
+    <a
+      href={href}
+      className="text-blue-600 underline underline-offset-2 hover:text-blue-800"
+      target="_blank"
+      rel="noopener noreferrer"
+      {...props}
+    >
+      {children}
+    </a>
+  ),
+  code: ({ className, children, ...props }) => {
+    // Inline code (no className from rehype)
+    const isInline = !className
+    if (isInline) {
+      return (
+        <code
+          className="bg-gray-100 text-pink-600 text-xs font-mono px-1 py-0.5 rounded"
+          {...props}
+        >
+          {children}
+        </code>
+      )
+    }
+    // Fenced code block — rendered by `pre > code`, handled in `pre`
+    return (
+      <code className={className} {...props}>
+        {children}
+      </code>
+    )
+  },
+  pre: ({ children, ...props }) => (
+    <pre
+      className="bg-gray-900 text-gray-100 text-xs font-mono rounded-lg px-3 py-2 overflow-x-auto my-2 leading-relaxed"
+      {...props}
+    >
+      {children}
+    </pre>
+  ),
+
+  // --- Lists ---
+  ul: ({ children, ...props }) => (
+    <ul className="list-disc list-inside mb-1.5 space-y-0.5 text-gray-800" {...props}>
+      {children}
+    </ul>
+  ),
+  ol: ({ children, ...props }) => (
+    <ol className="list-decimal list-inside mb-1.5 space-y-0.5 text-gray-800" {...props}>
+      {children}
+    </ol>
+  ),
+  li: ({ children, ...props }) => (
+    <li className="text-gray-800 leading-relaxed" {...props}>
+      {children}
+    </li>
+  ),
+
+  // --- Blockquotes ---
+  blockquote: ({ children, ...props }) => (
+    <blockquote
+      className="border-l-3 border-blue-300 bg-blue-50/50 pl-3 py-1 my-1.5 text-gray-600 italic"
+      {...props}
+    >
+      {children}
+    </blockquote>
+  ),
+
+  // --- Tables (GFM) ---
+  table: ({ children, ...props }) => (
+    <div className="overflow-x-auto my-2">
+      <table className="min-w-full text-xs border-collapse" {...props}>
+        {children}
+      </table>
+    </div>
+  ),
+  thead: ({ children, ...props }) => (
+    <thead className="bg-gray-50" {...props}>
+      {children}
+    </thead>
+  ),
+  th: ({ children, ...props }) => (
+    <th
+      className="border border-gray-200 px-2 py-1 text-left font-semibold text-gray-700"
+      {...props}
+    >
+      {children}
+    </th>
+  ),
+  td: ({ children, ...props }) => (
+    <td className="border border-gray-200 px-2 py-1 text-gray-700" {...props}>
+      {children}
+    </td>
+  ),
+
+  // --- Horizontal rule ---
+  hr: (props) => <hr className="my-3 border-gray-200" {...props} />,
+
+  // --- Strikethrough (GFM) ---
+  del: ({ children, ...props }) => (
+    <del className="text-gray-400 line-through" {...props}>
+      {children}
+    </del>
+  ),
+}
+
+interface MarkdownRendererProps {
+  content: string
+}
+
+export default function MarkdownRenderer({ content }: MarkdownRendererProps) {
+  return (
+    <ReactMarkdown remarkPlugins={[remarkGfm]} components={components}>
+      {content}
+    </ReactMarkdown>
+  )
+}

src/components/segments/DocumentCard.tsx

@@ -1,7 +1,8 @@
 import type { DocumentSegment } from '../../types/protocol'
+import type { LucideIcon } from 'lucide-react'
 import { FileText, FileImage, FileAudio, File } from 'lucide-react'
 
-const mimeIcons: Record<string, React.ComponentType<{ size?: number; className?: string }>> = {
+const mimeIcons: Record<string, LucideIcon> = {
   'text/': FileText,
   'image/': FileImage,
   'audio/': FileAudio,

src/components/segments/LongTextView.tsx

@@ -1,11 +1,12 @@
 import { useState } from 'react'
 import type { LongTextSegment } from '../../types/protocol'
 import { ChevronDown, ChevronRight, Text } from 'lucide-react'
+import MarkdownRenderer from '../MarkdownRenderer'
 
 export default function LongTextView({ segment }: { segment: LongTextSegment }) {
   const [collapsed, setCollapsed] = useState(segment.collapsed)
 
-  // Show first ~2 lines when collapsed
+  // Show first ~2 lines when collapsed (plain text preview, no markdown)
   const preview = segment.content.split('\n').slice(0, 2).join('\n')
 
   return (
@@ -16,7 +17,7 @@ export default function LongTextView({ segment }: { segment: LongTextSegment })
       >
         <Text size={14} className="text-gray-400" />
         <span className="text-xs text-gray-500 flex-1">
-          {collapsed ? '长文本素材' : '长文本素材'} · {segment.charCount} 字
+          长文本素材 · {segment.charCount} 字
         </span>
         <span className="text-blue-500 text-xs">
           {collapsed ? '展开' : '收起'}
@@ -26,15 +27,13 @@ export default function LongTextView({ segment }: { segment: LongTextSegment })
         </span>
       </button>
       {!collapsed && (
-        <div className="px-3 pb-3">
+        <div className="px-3 pb-3 max-h-96 overflow-y-auto">
-          <p className="text-sm text-gray-700 whitespace-pre-wrap leading-relaxed max-h-64 overflow-y-auto">
+          <MarkdownRenderer content={segment.content} />
-            {segment.content}
-          </p>
         </div>
       )}
       {collapsed && (
         <div className="px-3 pb-2">
-          <p className="text-sm text-gray-400 whitespace-pre-wrap line-clamp-2 italic">
+          <p className="text-sm text-gray-400 line-clamp-2 italic">
             {preview}
           </p>
         </div>

src/components/segments/TextSegmentView.tsx

@@ -1,9 +1,10 @@
 import type { TextSegment } from '../../types/protocol'
+import MarkdownRenderer from '../MarkdownRenderer'
 
 export default function TextSegmentView({ segment }: { segment: TextSegment }) {
   return (
-    <p className="text-gray-800 leading-relaxed whitespace-pre-wrap break-words">
+    <div className="text-gray-800">
-      {segment.content}
+      <MarkdownRenderer content={segment.content} />
-    </p>
+    </div>
   )
 }