Bump TypeBox to 1.3.7 so compiled validators guard array-specific keywords when null is accepted, and cover tool-argument validation with a regression test.
Breaking for extensions: TypeBox 1.3 removes deprecated APIs including Type.Base, Type.Awaited, Type.Promise, Type.AsyncIterator, Type.Iterator, Type.Options, and Value.Mutate. Extensions using these through Pi's bundled TypeBox aliases must migrate to supported TypeBox APIs.
Fixes#7003