Review and Refactoring of Models and Chat parameters

Hi there,

I would like to see the team review all models supported params, and automatically block those that are unsupported for specific models.

We have options to overwrite each model params, that is great, but insufficient.

Several models are missing params (prompt cache for example), and some models have params that don't apply to them (temperature or thinking for example).

I would like to see params per model, taking into consideration its capabilities. That means, unsetting default params and removing/adding those options conditionally, depending on each model.

In addition, some custom models do not support system prompts (ie: Gemma 3), but there is no option to disable it for the specific model. We need a toggle to enable/disable system prompts per model.

Finally, a big nuisance occurs when we change a model for a specific ongoing chat.

Because models don't support the same params, I think that the "overwrite settings" from the model we change to, should overwrite the chat settings (when switching models). Optionally, if I change for example, between thinking models to regular models, unsupported params should be ignored and not sent to the api.

This could easily be solved by adding some middleware or proxy to filter requests params, or by maintaining a list of capabilities for each supported model.