Module utils/typeGuards/mysimplestore

Type guard validating that a value matches the MySimpleStore search/list response envelope: an object with a products array whose items each carry the minimal id/slug/name/relative_url fields the supplier reads.

Type guard validating that a value matches the MySimpleStore product-detail response: an object with id/slug/name and an optional variants array. The per-variant shape is guarded at the point of use so a stray entry can't reject the whole response.