Target<T> class

Resolves to the nearest ancestor implementing T.

Built once, where the host is constructed, and read wherever it is needed:

late final _target = Target<AngleOwner>(this);

AngleOwner get target => _target.value;

The host resolves it on mount and drops it whenever its ancestry changes, so a node moved under a new parent finds the new one on its next read.

A nullable T makes the ancestor optional: value is null while the host is unmounted or has no such ancestor, instead of throwing.