Does creating a token copy count as having cast a spell?
No.

Casting a spell is a keyword action that involves placing a card (or copy thereof) on the stack, making choices, optionally activating mana abilities, and paying its cost.

Activating an activated ability (such as Prototype Portal's second abiliy) is not casting a spell.

Creating a copy of an object is not casting a spell (even if the object being copied is a spell).

Putting an artifact on the battlefield is not casting a spell.