Allow `-max-ai-credits=0` when using local models

### Describe the feature or problem you'd like to solve

I'd like to be able to use local models with `/remote` without the possibility of accidentally using credits in that session

### Proposed solution

Remote the validation on `-max-ai-credits` that requires that it is >= 30.

### Example prompts or workflows

_No response_

### Additional context

The limit of 30 seems totally arbitrary, and when using a local model it doesn't mean anything. When testing with local models, it would be nice to know for sure that we can't accidentally use credits.

Start by locating the validation for the `-max-ai-credits` option and the code that identifies local models when `/remote` is used. Confirm the current minimum of 30, then verify that a value of 0 is accepted for the local-model workflow and that the session cannot use credits unexpectedly.

Written by the indexing model from the issue text.