DelegationScope is orthogonal to ShellClass — an Application session
can have delegation authority to orchestrate System operations on
remote targets (the Infrastructure shell pattern for Ansible/Terraform).
TargetSelector supports: None, Hosts (explicit list), LabelSelector
(deferred to K8s API), TrustDomain (all hosts). Default: denied
(fail-closed).
DelegationDecision: Permitted, Denied (with reason), Deferred (for
async label resolution).
Added delegation field to SessionScope with #[serde(default)] for
backward-compatible deserialization.
7 unit tests for delegation scope checking.
Signed-off-by: Tyler King <tking@guildhouse.dev>
Signed-off-by: Tyler J King <tking727@gmail.com>