Widen the "swatch stripe" on the left side of the Color Picker

### Description of the new feature / enhancement

Increase the width of the swatch stripe on the left side of the Color Picker, preferably 2x-3x the current width. Optionally hide this behind a settings toggle.

### Scenario when this would be used?

I have moderate color blindness, and when samples are small I have a very difficult time telling the difference. When there is more area to view the color, it really helps me. I'll never really be able to see the colors, but this at least allows me to see that there is a difference between them even if I can't name the color.

I didn't realize for a long time that the color stripe on the left was a list of clickable "nearby" colors because of the narrowness.

### Supporting information

_No response_

The issue does not name a file, test, or entry point. Start by locating the Color Picker UI and its left-side swatch stripe, then verify the stripe can be made 2x–3x wider and assess whether a settings toggle is needed; done means the nearby-color list is more visible and usable.

Written by the indexing model from the issue text.