feat: Threads should show "Jan using <model_name>" instead of "Assistant"

[dan-menlo]

Note: This is a Product discussion, not confirmed as an issue yet.

Objective

• Threads view should educate the user on Jan as an Assistant, but also show the model name
• I would like to propose us have the Assistant reply as "Jan using ", instead of Assistant
• This enables us to push "Jan" as a default Assistant

Screenshots

[imtuyethan]

We also need to find a way to create Thread Titles, ChatGPT style - right now everything just says "New Thread"

[freelerobot]

I think users like editting thread titles. If not, then we're also tracking #979