Restore a white background contact sheet option for home printing

[cfowlerdesign]

Could we bring back an optional white background for contact sheets, with dark labels for readability?

I'm using NegPy 0.63.0 on macOS. The darkroom contact-sheet redesign in #1244 removed the previous background/label colour controls. I understand the aim of reproducing a traditional contact print, but the black background makes the sheets much less practical to print at home.

Why this matters

I'd like to print contact sheets to review my photographs on paper. Filling the spaces around the photographs with black uses a lot of printer ink, especially across multiple rolls. A white background would make this a much more affordable everyday workflow and leave room for handwritten notes.

Suggested option

A simple White background / Ink-saving toggle in the Contact Sheet dialog would be enough:

• White page margins and spaces between frames/strips, rather than large areas of black.
• Dark labels and frame numbers so they remain readable.
• No changes to the photographs themselves or their edits.
• Keep the existing darkroom appearance available, including as the default.

Restoring the full colour picker would also work, but a basic black/white choice would solve my printing need. I'm not asking to undo the new contact-sheet layout—just to make it suitable for home printing as well as darkroom-style presentation.

Thanks for considering it.

[marcinz606]

#1320