Missing license file for the codebase

Hi Hack Club HQ! While I may be considered inactive in the community since months ago ([context](https://gitlab.com/andreijiroh-dev/hackclub-final-signoff/-/blob/main/README.md?ref_type=heads)), I am reaching here to ask the question "which license does Hack Club Identity/Auth codebase apply here"? I could file a patch with the AGPL-3.0 as the license to match HCB's, but because there are contributors from the community this ticket exists to avoid possible headaches.

**Additional context**: I am currently maintaining the unofficial GitLab.com namespace for @hackclub-community (cue me keeping read-only mirrors in case GitHub goes down again), more specifically for @hackclub-alumni Society subgroup and I am in the process of renewing the complimentary Ultimate plan as part of GitLab for Open-source Program ([see requirements in the GitLab Handbook](https://handbook.gitlab.com/handbook/marketing/developer-relations/programs/open-source-program/#who-qualifies-for-the-gitlab-for-open-source-program)). If anyone's using GitLab.com and want to take over the admin chores there, let me know so I can do the migration flow behind the scenes.

Start by inspecting the repository root for existing license or contribution guidance, then review the issue's AGPL-3.0 suggestion and the repository's community contribution context. The work is done when maintainers decide which license applies and the corresponding license file is added to the codebase.

Written by the indexing model from the issue text.