Model change in any case

**Situation:**
Because of budget restrictions a model ran out of tokens.

**Problem:**
I can not "maintain" a rooms knowledge nor can I change the model/provider, since the later is only possible after the rooms knowledge is maintained.

To help me out I changed the model/provider setting in the current thread.json

I should at least change the provider and keep the model (changing from github copilot subscription to openAI with the same model)...

Start by examining the current thread.json handling and the code path for maintaining a room's knowledge. Trace how the model and provider are selected, then verify that the provider can change while the existing model is retained and knowledge maintenance remains possible.

Written by the indexing model from the issue text.