feat: users can choose which model(s) to chat with

[freelerobot]

Problem
Thanks to @louis-jan 's PR: #361

Users can chat with multiple models (gpt via API + a locally running model)

We should let users choose which model(s) they are chatting with

Success Criteria

• Users can choose a model to chat with
• Users can select multiple models to chat with (local + api), or even (local + local if it fits on ram)

See designs:

Additional context
Add any other context or screenshots about the feature request here.

[freelerobot]

@louis-jan who is best to pick up this issue later? Can you help assign. I noticed you more or less have the core logic implemented, i.e. where you had 2 models simultaneously respond to 1 user query

[louis-menlo]

@louis-jan who is best to pick up this issue later? Can you help assign. I noticed you more or less have the core logic implemented, i.e. where you had 2 models simultaneously respond to 1 user query

@namchuai can take ownership of this (assigned), and I will support the ability to enable/disable providers

[louis-menlo]

this enhancement will also address #386 (can just select active providers to chat with)

[freelerobot]

Closing this as our UI is undergoing significant change. We can reopen in the future.