Replaced the `i18n` and `toml` dependencies with Fyne's built-in language system for localization management. Updated the `Localizer` implementation to handle translations using JSON files and embed functionality. Simplified language selection and persisted settings via Fyne's preferences API.
Replaced bbolt-based database handling with Fyne built-in preferences for storing application settings. Deleted migration logic, database initialization, and error handling related to bbolt, simplifying the codebase and reducing external dependencies.
Ensure the "Added Files" tab is automatically selected after users drag and drop files for conversion. This improves user experience by guiding them to the newly added content.
Implemented functionality to handle single file drag-and-drop in the UI, including error handling for multiple files and directories. Updated localization files to support new messages related to drag-and-drop usage and errors.
Introduced `DirectoryForSaving` for managing directory paths persistently. Integrated the new setting into relevant modules, ensuring the selected directory is saved and loaded across sessions.
