improvement· Models
Unconfigured runs default to the oh-my-pi engine
When nothing sets `engine`, runs now use oh-my-pi with `anthropic/claude-sonnet-4-6` instead of claude-code with `sonnet`.
The model is the same Claude Sonnet 4.6; only the harness around it changed. Connected API keys and subscriptions still pick their own default when you set neither engine nor model, so the runs that notice are mostly Monthly-plan tasks on our Anthropic key with nothing configured. One kind of config breaks: a .sinatrarc or personal override that names a bare Claude model such as sonnet, opus or haiku without an engine, for the agent or for planning and brainstorming, is now rejected, because those names only exist on claude-code. Add engine: claude-code to keep it running as before.
#1272