Feature: Enable Custom Theme Configuration

Description: We want to allow users to configure their own themes! Implement functionality so users can define a custom theme with their own colors and apply it to the application. This should support adding, editing, and selecting a custom theme dynamically.

File: apps/web/src/themes.ts

Task:

• Refactor the themes object to support user-defined themes.
• Add the ability for users to provide their own color values and save them.
• Ensure the app can apply the custom theme in the same way as existing themes.
• Maintain the structure and compatibility with existing themes.

Reference:

• See existing themes in themes.ts for structure.