Assign a gift card to another user?

Problem/Motivation

I have created a gift card type, and a product type with the gift card trait added on the variation. I am able to purchase a gift card product but I don't know what to do with it next.

How do I assign this gift card to another user so that they can use it as a full or partial payment on their purchases?

Steps to reproduce

1. Create a gift card type
2. Create a new product type with the gift card trait added
3. Add a git card product
4. Purchase a gift card product

Proposed resolution

Unless there is an existing way to do this that I'm missing...

Add a user reference field to the checkout form as a checkout pane where the purchaser can enter the username of another user to send the gift card to, and/or add a form to the purchaser's order page that allows them to assign a gift card to a user post-purchase.

Remaining tasks

User interface changes

API changes

Data model changes