feat: implement Anthropic native PDF support with document preservation

- Add comprehensive debug logging throughout PDF processing pipeline
- Refactor attachment processing to separate image and document handling
- Create distinct addImageURLs(), addDocuments(), and processAttachments() methods
- Fix critical bugs in stream handling and parameter passing
- Add streamToBuffer utility for proper stream-to-buffer conversion
- Remove api/agents submodule from repository

🤖 Generated with [Claude Code](https://claude.ai/code)

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

client/src/components/Messages/MessageContent.tsx

@@ -1,7 +1,7 @@
 import React from 'react';
 import { useMessageProcess } from '~/hooks';
 import type { TMessageProps } from '~/common';
-// eslint-disable-next-line import/no-cycle
+
 import MultiMessage from '~/components/Chat/Messages/MultiMessage';
 import ContentRender from './ContentRender';
 
@@ -64,7 +64,7 @@ export default function MessageContent(props: TMessageProps) {
             </div>
           </div>
         ) : (
-          <div className="m-auto justify-center p-4 py-2 md:gap-6 ">
+          <div className="m-auto justify-center p-4 py-2 md:gap-6">
             <ContentRender {...props} />
           </div>
         )}