planning: Jan Theme Extensions API

[dan-menlo]

Goal

• Jan has a clear Themes API that users can easily configure to change app appearance
  • Themes are separate Github repos
  • Inspo: Obsidian, VSCode
• What do we need to change
  • Instead of Joi
  • Use a more standard library? e.g. shadcn

Tasklist

• @urmauur to propose Themes API and framework
• To document in https://github.com/orgs/janhq/discussions/3566
• feat: add more customization for default color themes #3100

[dan-menlo]

@urmauur I'll be shifting this to Sprint 22, to allow you to focus on Ichigo Demo, Jan + Cortex sites