feat(ui): customizable colors

[dazy-ds]

Feature description

Enable UI color customization from the backend by supporting one of two possible approaches:

• Passing coded color values from the backend, which the frontend then uses to generate the required palette (e.g., via chroma.js).
• Providing a CSS file with a predefined structure that defines the desired color scheme.

Before implementation, research should be conducted to determine which of these approaches works best in combination with HeroUI, the component library currently in use.

Motivation

Currently, changing the UI color scheme requires rebuilding and redeploying the frontend. This feature will allow runtime configuration of colors, removing the dependency on frontend redeployments. As a result, users will be able to define and adjust their desired color schemes more easily and flexibly.

Additional context

• Compare the trade-offs of coded values vs. structured CSS file.
• Investigate best practices for dynamic theming with HeroUI.
• Clarify how many base colors should be backend-defined to generate a full palette (if the coded values approach is selected).
• Consider fallback behavior if the backend provides invalid or incomplete input.
• Ensure that the implementation does not introduce significant runtime overhead.