Minor GUI improvements / addition of warning messages

[swtman]

Hello, i came across this app and decided to make some little gui improvements and validation checks!
I added branding elements, implemented a simple input validation for the "Add " button and added feedback for the remove and modify mechanisms. Specifically:

GUI

• Added the application icon (SNAKE.png) to the main window title bar and the various pop up that can be opened
• Added the banner image (banner.png) to the top of the main interface (noticed them in the Assets and thought why not showcase them in the app also)
• Updated "Step" labels (1,2,3) to use a bold font for better visual guidance
• Slightly change the DataView display
• Set min size of the main window appropariately to fit the banner appropariately (no changes about max size)
• Changed label "Backround" to "Backround Sorting" so that is more clear what it is about (personally, at first i though it was about the main window backround :) )
• Added hover tooltips on the buttons to give the user a hint about what every button does

Validation Handling

• Add rule : Users can no longer save rules with empty paths or extensions; an error popup now appears if fields are missing
• Modify/Remove rule : Added checks to the "Modify" and "Remove" buttons in the main view. If no row is selected, a warning popup now alerts the user instead of failing silently
• Remove rule : Updated the Remove Rule confirmation dialog. It now explicitly lists the Folder Path and Extensions of the rule being deleted, rather than just a simple"Are you sure?" message. Now there is more certainty about which rule is about to be removed

Really enjoyed working on these UI improvements. Hope you find them useful!
Thanks for taking the time to review this! I look forward to your feedback!
Here are some screenshots of what is mentioned above!