Session control

session.stop(); session.pause(); session.resume()
await session.input("command", {"name": "skip"})

User input: a stage declares allowed_inputs and awaits await self.wait_input("user_input", timeout=...); input is delivered from outside with await session.input("user_input", {...}). The payload is validated against the payload_schema from the declaration.

Snapshots: session.snapshot() returns a dict, Session.from_snapshot(snap) restores the session, and run() resumes from the saved node.

The same commands are buttons in the editor's debug panel: continue, one step, stop, and the pause between nodes.