fix text input and colour, add rudimentary drag n drop support

add unit tests for checking indentation with tab key in TUI

fix broken indent feature for TUI

refactor GUI and TUI into separate modules

cleanup obsolete module, fix unit tests. Also, wrap status bar

add slint-based graphical user interface

Add support for deleting entries and fix program abort on non-ascii character entry

initial implementation by Claud Sonnet 4

initial commit with the requirements for the app