chore: release 0.48.1

[marcinz606]

Version bump + changelog for 0.48.1.

• New: Printing Notes — Export tab previews a marked-up work print on canvas (Shift+N) and writes it as <stem>_notes.jpg.
• New: Local Grade per dodge/burn mask — each mask prints at its own contrast, in ISO-R points off the frame's Grade.
• Change: Dodge/burn now in stops — mask slider is "Burn", ±2 stops, default 0; old saves migrate.
• Fix: Slider tooltips work on the label too — hovering a title showed only the reset hint.