Introduce smooth UI transitions by adding opacity-based animations. Import QGraphicsOpacityEffect and add animate_widget_fade_in, animate_widget_fade_out, and set_status_message_animated to cross-fade status text and fade buttons in/out. Update signal handlers and download flow to use the new animated status setter and fade methods instead of direct setText/setVisible calls. Keep animation references on widgets to avoid premature GC and remove effects after fade-out.
Initialize an error buffer and collect yt-dlp "ERROR:" output lines during direct command runs. When the process exits non‑zero, emit a more informative error using the last two captured error lines (falling back to the generic return-code message if none were captured). Also ensure the buffer is present before appending and keep the existing delay/cleanup flow.
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.
Renamed 'src/core' to 'ytsage/core' and updated all internal imports to use relative paths. This improves package structure and ensures correct module resolution after the directory move.
Moved utility modules from src/utils/ to ytsage/utils/ and updated all relative imports accordingly. Adjusted docstring usage examples and fixed a path reference in LocalizationManager to reflect the new directory structure.