Introduce a new `MainSettings` view for managing application settings, including language and theme selection. Implement theme management methods in the `setting` package to handle theme initialization, retrieval, and updates.
Introduce logic and UI for selecting and persisting a directory to save converted files. Extend existing components with directory selection buttons, message updates, and storage preferences.
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.
