bug: persist model preferred by user

[NeerajReddyK]

The AI model selected by user is not being persisted on refreshing.

[NeerajReddyK]

I am working, will create a PR in few mins

[NeerajReddyK]

https://github.com/code100x/1ai/pull/151
This is the URL for PR. I didn't connect to the right issue I guess. My first PR.