run-app takes #:screenshot, a path: the window saves a PNG of itself there
once it is shown and laid out, at twice its size, and closes. It defaults to
the environment variable BJOGUI_SCREENSHOT, so any program can be pictured
with no change. docs/todo.png is examples/todo.bjo, taken that way.
🤖 Generated with [ECA](https://eca.dev) (anthropic/claude-opus-4-8)
Co-Authored-By: eca-agent <git@eca.dev>
