Phase 0.2: migrate remaining SVGs to lucide-react icons

frontend/src/components/comm/blocks/FileBlock.tsx

@@ -1,5 +1,6 @@
 import React from 'react';
 import type { MessageBlock } from '@/store/commStore';
+import { Download, FileText } from 'lucide-react';
 
 interface FileBlockProps {
   block: MessageBlock;
@@ -14,37 +15,11 @@ function formatFileSize(bytes: number | undefined): string {
 }
 
 const fileIcon = (
-  <svg
-    className="w-8 h-8 text-secondary-400"
-    fill="none"
-    viewBox="0 0 24 24"
-    stroke="currentColor"
-    aria-hidden="true"
-  >
-    <path
-      strokeLinecap="round"
-      strokeLinejoin="round"
-      strokeWidth={1.5}
-      d="M14 2H6a2 2 0 00-2 2v16a2 2 0 002 2h12a2 2 0 002-2V8z M14 2v6h6 M8 13h8 M8 17h5"
-    />
-  </svg>
+  <FileText className="w-8 h-8 text-secondary-400" aria-hidden="true" strokeWidth={1.5} />
 );
 
 const downloadIcon = (
-  <svg
-    className="w-4 h-4"
-    fill="none"
-    viewBox="0 0 24 24"
-    stroke="currentColor"
-    aria-hidden="true"
-  >
-    <path
-      strokeLinecap="round"
-      strokeLinejoin="round"
-      strokeWidth={2}
-      d="M4 16v1a3 3 0 003 3h10a3 3 0 003-3v-1m-4-4l-4 4m0 0l-4-4m4 4V4"
-    />
-  </svg>
+  <Download className="w-4 h-4" aria-hidden="true" strokeWidth={2} />
 );
 
 const FileBlock: React.FC<FileBlockProps> = ({ block }) => {