Update customColors.js

[PrometheusDante]

Hey there,

I expanded the node color customization by adding options for coloring the title bar and node background individually in addition to your original option to color both at once. Another tweak was turning the .onchange event handler to .oninput to have a live preview of the selected color before confirming the choice with the ok button.

In case you want to merge it, here it is. If you'd like something changed, I'll do my best. 👌 Thank you for your time and hard work!

https://github.com/user-attachments/assets/46e015f5-30f5-4ef2-bd2b-5197389cd76e