fix: shadow markdown (#1871)

问题:[Bug]: 当模型回复的html代码没有正确在代码框中时，html代码内容会影响到UI界面 #1767
原因:解析html之后css会污染应用样式
解决:将markdown完全放入shadow dom中,shadow dom天然隔绝样式,即可解决

* feat: Conditionally hide thinking loader for paused messages

* feat: Implement Shadow DOM for Markdown rendering

* feat: Add StyleProvider to Shadow DOM Markdown rendering

* fix: Refactor Markdown rendering with inline ShadowDOM component

Modify ReactMarkdown component to use style component for ShadowDOM rendering instead of wrapping component, simplifying the rendering approach

---------

Co-authored-by: lizhixuan <zhixuan.li@banosuperapp.com>

src/renderer/src/components/MarkdownShadowDOMRenderer.tsx

@@ -0,0 +1,63 @@
+import { StyleProvider } from '@ant-design/cssinjs'
+import React, { useEffect, useRef } from 'react'
+import { createPortal } from 'react-dom'
+import { StyleSheetManager } from 'styled-components'
+
+interface Props {
+  children: React.ReactNode
+}
+
+const ShadowDOMRenderer: React.FC<Props> = ({ children }) => {
+  const hostRef = useRef<HTMLDivElement>(null)
+  const [shadowRoot, setShadowRoot] = React.useState<ShadowRoot | null>(null)
+
+  useEffect(() => {
+    const host = hostRef.current
+    if (!host) return
+
+    // 创建 shadow root
+    const shadow = host.shadowRoot || host.attachShadow({ mode: 'open' })
+
+    // 获取原始样式表
+    const markdownStyleSheet = Array.from(document.styleSheets).find((sheet) => {
+      try {
+        return Array.from(sheet.cssRules).some((rule: CSSRule) => {
+          return rule.cssText?.includes('.markdown')
+        })
+      } catch {
+        return false
+      }
+    })
+
+    if (markdownStyleSheet) {
+      const style = document.createElement('style')
+      const cssRules = Array.from(markdownStyleSheet.cssRules)
+        .map((rule) => rule.cssText)
+        .join('\n')
+
+      style.textContent = cssRules
+      shadow.appendChild(style)
+    }
+
+    setShadowRoot(shadow)
+  }, [])
+
+  if (!shadowRoot) {
+    return <div ref={hostRef} />
+  }
+
+  return (
+    <div ref={hostRef}>
+      {createPortal(
+        <StyleSheetManager target={shadowRoot}>
+          <StyleProvider container={shadowRoot} layer>
+            {children}
+          </StyleProvider>
+        </StyleSheetManager>,
+        shadowRoot
+      )}
+    </div>
+  )
+}
+
+export default ShadowDOMRenderer

src/renderer/src/pages/home/Markdown/Markdown.tsx

@@ -1,13 +1,14 @@
 import 'katex/dist/katex.min.css'
 import 'katex/dist/contrib/copy-tex'
 
+import MarkdownShadowDOMRenderer from '@renderer/components/MarkdownShadowDOMRenderer'
 import { useSettings } from '@renderer/hooks/useSettings'
-import { Message } from '@renderer/types'
+import type { Message } from '@renderer/types'
 import { escapeBrackets, removeSvgEmptyLines, withGeminiGrounding } from '@renderer/utils/formats'
 import { isEmpty } from 'lodash'
-import { FC, useMemo } from 'react'
+import { type FC, useMemo } from 'react'
 import { useTranslation } from 'react-i18next'
-import ReactMarkdown, { Components } from 'react-markdown'
+import ReactMarkdown, { type Components } from 'react-markdown'
 import rehypeKatex from 'rehype-katex'
 // @ts-ignore next-line
 import rehypeMathjax from 'rehype-mathjax'
@@ -52,11 +53,12 @@ const Markdown: FC<Props> = ({ message }) => {
 
   return (
     <ReactMarkdown
-      className="markdown"
       rehypePlugins={rehypePlugins}
       remarkPlugins={[remarkMath, remarkGfm]}
+      className="markdown"
       components={
         {
+          style: MarkdownShadowDOMRenderer,
           a: Link,
           code: CodeBlock,
           img: ImagePreview