Model selection is resetted all the time

I have four models GPT-5.6-Sol, GPT-5.6-Terra, GPT-5.6-Luna, GPT-5.6 activated. I already set Terra as default for memorize and review. But on the room tiles it is always Sol. I can change it one time. But as soon as I start the next session (with remember or drop) it switches back to sol.

Expectations:
- The selection on the room tiles is respected and persisted.
- There is default setting for which model to use for room conversions.

Start by tracing how the model selected on room tiles is stored and how a new session begins for remember and drop actions. Verify the default model setting and session transitions, then confirm that a selected model remains after starting another session and that room conversions use the configured default.

Written by the indexing model from the issue text.