SnapManager (prototype)
GTK-4 Prototype for managing updates and issues on snaps.

Work in progress.
Highlights
- Snap & apt lists with friendly error messages and guided actions.
- Snap Problem Solver that interprets diagnostics and recommends fixes.
- A small snap→apt database (
snapmanager/data/snap_to_apt.json) that the UI consults before suggesting apt replacements, so it can point to the right deb or tell you when only a snap build exists.