Refactor code structure and remove redundant changes

src-old/components/blog/MarkdownRenderer.tsx

@@ -0,0 +1,75 @@
+import ReactMarkdown from 'react-markdown';
+import rehypeSanitize, { defaultSchema } from 'rehype-sanitize';
+import { cn } from '@/lib/utils';
+
+interface MarkdownRendererProps {
+  content: string;
+  className?: string;
+}
+
+// Custom sanitization schema with enhanced security
+const customSchema = {
+  ...defaultSchema,
+  attributes: {
+    ...defaultSchema.attributes,
+    a: [
+      ...(defaultSchema.attributes?.a || []),
+      ['rel', 'noopener', 'noreferrer'],
+      ['target', '_blank']
+    ],
+    img: [
+      ...(defaultSchema.attributes?.img || []),
+      ['loading', 'lazy'],
+      ['referrerpolicy', 'no-referrer']
+    ]
+  }
+};
+
+/**
+ * Secure Markdown Renderer with XSS Protection
+ * 
+ * Security features:
+ * - Sanitizes all user-generated HTML using rehype-sanitize
+ * - Strips all raw HTML tags (skipHtml=true)
+ * - Enforces noopener noreferrer on all links
+ * - Adds lazy loading to images
+ * - Sets referrer policy to prevent data leakage
+ * 
+ * @see docs/SECURITY.md for markdown security policy
+ */
+export function MarkdownRenderer({ content, className }: MarkdownRendererProps) {
+  return (
+    <div
+      className={cn(
+        'prose dark:prose-invert max-w-none',
+        'prose-headings:font-bold prose-headings:tracking-tight',
+        'prose-h1:text-4xl prose-h2:text-3xl prose-h3:text-2xl',
+        'prose-p:text-base prose-p:leading-relaxed',
+        'prose-a:text-primary prose-a:no-underline hover:prose-a:underline',
+        'prose-strong:text-foreground prose-strong:font-semibold',
+        'prose-code:bg-muted prose-code:px-1.5 prose-code:py-0.5 prose-code:rounded prose-code:text-sm',
+        'prose-pre:bg-muted prose-pre:border prose-pre:border-border',
+        'prose-blockquote:border-l-4 prose-blockquote:border-primary prose-blockquote:italic',
+        'prose-img:rounded-lg prose-img:shadow-lg',
+        'prose-hr:border-border',
+        'prose-ul:list-disc prose-ol:list-decimal',
+        className
+      )}
+    >
+      <ReactMarkdown 
+        rehypePlugins={[[rehypeSanitize, customSchema]]}
+        skipHtml={true}
+        components={{
+          a: ({node, ...props}) => (
+            <a {...props} rel="noopener noreferrer" target="_blank" />
+          ),
+          img: ({node, ...props}) => (
+            <img {...props} loading="lazy" referrerPolicy="no-referrer" />
+          )
+        }}
+      >
+        {content}
+      </ReactMarkdown>
+    </div>
+  );
+}