Introduce a new layout system for managing main window content and tabs. Integrate file selection and drag-and-drop functionality for adding files to the conversion list, with automatic tab switching to "Added Files". Refactor existing components to support these features.
Introduce a new UI for configuring FFmpeg, FFprobe, and FFplay paths with file selection and error handling. Add platform-specific logic for downloading and extracting FFmpeg binaries directly within the application, improving user experience.
