Mosaic v0.8.1

A small polish release focused on the tool palette and window restoration.

- Window position and size are now restored on launch instead of resetting each time.
- Removed single-letter keyboard shortcuts for tools (V/T/L/N/A/P/I/X) to prevent accidental tool switches while working in terminals.
- The Delete tool now reverts to the pointer after deleting an item, so a second click won't keep deleting.
- Tooltips updated to match — hotkey hints removed.