CLI 5.1.0

A turn now carries the directories it may work in. The platform sends them with each exec.start, and the daemon admits them for that exec only, so an agent whose workspace sits outside the managed tree (a coding agent that shares a sandbox with another framework) no longer needs a separate registration round trip before every turn. The daemon advertises this as exec.roots.v1; a platform that needs it on an older daemon asks for an update instead of failing mid-turn.