feat: Allow users to mark models as favourites

[eckartal]

• I have searched the existing issues

Is your feature request related to a problem? Please describe it

Switching between different models frequently is cumbersome without a way to manage favorites or custom presets.

Describe the solution

Add a feature to mark models as favourites.
Allow users to create and save custom presets.

Teachability, documentation, adoption, migration strategy

No response

What is the motivation / use case for changing the behavior?

This will improve efficiency for users who regularly switch between models like groq llama 3 and gpt-4o. It will make the workflow faster and more convenient.

Related comment: https://www.reddit.com/r/LocalLLaMA/comments/1dk7gye/comment/l9gyayy/?context=3

[imtuyethan]

Will allow users to create/save custom preset in #2845
I'll change this ticket's user story to "Mark models as favourite"