Update app.py

app.py

@@ -7,7 +7,7 @@ from datetime import datetime
 from config.settings import Settings
 from core.file_scanner import FileScanner, FileInfo
 from services.llm_service import LLMService
-from typing import List, Set
+from typing import List, Set, Optional
 from main import DirectoryStructureScanner, MarkdownGenerator
 
 class StreamlitFileWriter: