MxAccessError.Unwrap returned e.Command directly; on the HRESULT-only path
Command is a nil *CommandError, so Unwrap returned a non-nil error wrapping
a typed nil and errors.As bound a nil *CommandError. Unwrap now returns an
untyped nil when Command is nil. Added errors_test.go regression coverage
for the HRESULT-only and populated-Command paths.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Joseph Doherty