[FEAT]: Deprecate default thread - Thread UX improvements

[timothycarambat]

What would you like to see?

We should finally remove the default thread function. It has historically existed since we added threads after we had workspace. The flow should be similar to the video here.

As a user, I click on a workspace:
If no threads are present:

• I should see an italic "New thread" title that is currently selected. The first message will update its name and save the thread.
• I cannot see the "Create thread" button since I am on the only active thread.

If threads are present in a workspace:

• I am automatically loaded into the first available thread if none is selected.
• We can also keep track of last active thread within a workspace to when navigating to generic workspace path we auto-load the last active thread. If they click a specific thread, we bring them to that thread.
• Can also create a new thread in this UI.

For backwards compatibility:

• If the user has chats in the default thread, we will show it. If it is empty, we will not surface this thread to the user and the first condition above will apply here for UX.

[scottybo]

Great to see this being implemented! A few thoughts on the implementation:

Clicking on a workspace with threads

I'd recommend against loading the most recent thread when going to a workspace. Usually when returning to a chat platform, you're going to start a new conversation. To remove friction, when you click on a workspace, the chat window should show and only when a conversation is started does it create the new thread.

Alternatively, perhaps this could be a setting as I image preferences will vary on this one.

Backwards compatibility

It would be good to be able to delete the default thread - I've frequently accidentally started a "new" conversation in the default thread.