zenith<T> method
Resolves the value for key from the nearest ZenithTenantScope's
container, or throws if not registered.
Implementation
T zenith<T>(ZenithKey<T> key) {
final scope = ZenithScopeProvider.of(this);
final node = scope.container.maybeNode<T>(key);
if (node == null) {
throw StateError('No node registered for $key in scope "${scope.id}".');
}
return node.value;
}