Save Folder Fix + Visual Updates

• Modal now expands to fill window vertically
• "Add Save Folder" button fixed
• "Delete Save Folder" functionality fixed
• Saving happens in "transactions" that can be reversed if something goes wrong along the way, reducing the risk of Pokémon loss or duplication across saves
• Minor aesthetic improvements

What's Changed

• Add folder fix by @andrewbenington in #37
• misc: fix save folder deletion + update some visuals by @andrewbenington in #39

Full Changelog: v0.4.1...v0.4.2