Function delete 

pub fn delete(
    root: &AppRoot,
    agent: &AgentId,
    profile: &ProfileName,
) -> Result<DeleteOutcome>

Removes the profile directory for agent under the same exclusive lock link and update take (spec §18), re-checking delete_target and blocking_references inside it: the advisory checks outside the lock can be seconds stale, and a deletion that never leaves a mapping or the global default pointing at nothing is the invariant this function exists to hold (SP5a design §3).