@type t() :: %ExecutionPlane.Contracts.BoundarySessionDescriptor.V1{
  approval_refs: [String.t()],
  artifact_refs: [String.t()],
  attach_state: String.t(),
  boundary_session_id: String.t(),
  contract_version: String.t(),
  decision_id: String.t(),
  extensions: map(),
  lease_refs: [String.t()],
  persistence_posture: map() | nil,
  policy_echo: map(),
  session_status: String.t(),
  workspace_ref: String.t()
}