Replace entry.get('file_size', 0) with entry.get('file_size') or 0 in HistoryDelegate (ytsage_dialogs_history.py) to treat None as 0. This prevents TypeError when comparing None > 0 and ensures file size formatting/display only occurs for positive sizes.
Moved all files from src/gui/ to ytsage/gui/ and updated import statements to use relative imports within the new package structure. This improves modularity and prepares the codebase for distribution as a proper Python package.