open-prose 是做什麼的？
Activate when the user types prose ..., opens a .prose.md file with kind: frontmatter, opens a .prose file, or asks for reusable multi-agent orchestration. Treat prose run ... as an in-session instruction: embody the OpenProse VM yourself; do not shell out to a prose binary. On activation read the Markdown contract, select a state backend, wire responsibilities, execute with host primitives, and persist run state under the selected OpenProse root. Decline for one-shot questions — a plain prompt is often the right answer.