Support 'set model' in client

[dillera]

Allow clients to set the model used on the back-end via SET command:

set model gemini-3-ad-free
set model dall-e-3
set model gpt-4o

set model local-model
 

Those are just a few examples- but the idea is allow a string say up to 40 char to be added in for the model name.

The server as it parses the tokens will then switch API calls to various models based on the name 'set' from the client.

[brad-colbert]

Fix is in PR (#3)

[brad-colbert]

@dillera close this bad boy 👍