fix: resolve Firefox display issue in md-render --edit mode

Fixed JavaScript execution order problem where MarkitectEditor class
was being instantiated before it was defined, causing Firefox to fail
rendering the HTML page.

Changes:
- Moved editor script definitions before DOMContentLoaded event handler
- Ensured proper script execution sequence for cross-browser compatibility
- Maintained existing functionality for regular (non-edit) mode rendering

Fixes #154: Html generated by "md-render --edit" does not show in firefox

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

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

markitect/document_manager.py

@@ -551,6 +551,9 @@ class DocumentManager:
         const markdownContent = {js_markdown_content};
         {editor_config}
 
+        // Define editor class and scripts first
+        {editor_scripts}
+
         document.addEventListener('DOMContentLoaded', function() {{
             const contentDiv = document.getElementById('markdown-content');
             if (contentDiv && typeof marked !== 'undefined') {{
@@ -564,8 +567,6 @@ class DocumentManager:
                 {'markitectEditor = new MarkitectEditor();' if edit_mode else ''}
             {'}}' if edit_mode else ''}
         }});
-
-        {editor_scripts}
     </script>
 </body>
 </html>"""