docs: drop removed bb-plugin-screenshots skill reference
SM
11d ago+0-1
The bb-plugin-screenshots skill was removed from dotfiles (25293e5) and its tooling is gone; drop the dead AGENTS.md trap that pointed to it. No installed skill replaces it for plugins, so no substitute is named.
Summary by cubic
Removes the bb-plugin-screenshots skill reference from AGENTS.md after the skill was removed from dotfiles. The docs no longer point to tooling that doesn't exist.