[Feature] Add configuration flags for non-interactive mode

[james2doyle]

Description

I want to be able to pick the provider and model when running in non-interactive mode

Use Case

If you want to use nanocoder with multiple instances of the same CLI tool, you need to be able to pass provider and model details to the run command.

https://getpolyscope.com/
https://github.com/aarondfrancis/counselors

Here are two tools that you need CLI flags for.

It would also be nice to start the nanocoder session with a specific provider or model selected.

Proposed Solution

Just allow the model and provider to be set when using run

nanocoder --provider openrouter --model google/gemini-3.1-flash-lite-preview run "my prompt goes here still"

If my default provider + model are local, this allows me to quickly switch to a remote one when necessary without having to run through different slash commands or editing the config or ENV.

Alternatives Considered

I saw some issues for allowing the ENV to control config. I think this works nicely with both of those options as well.

Additional Context

• I have searched existing issues to ensure this is not a duplicate
• This feature aligns with the project's goals (local-first AI assistance)

[will-lamerton]

This is a great suggestion. We will bundle into the next release :)