[Feature Request] Set up authentication

# Overview
Set up authentication using NextAuth. The currently supported sign-in options are google, discord, and google internal acmutd.co.
# Tasks
- [x] Install & Configure Next-Auth
- [x] Add Google provider
- [x] Add Discord provider
- [x] Add Google internal acmutd.co provider
- [x] Create auth wrapper component
- [x] Configure FaunaDB adapter
- [ ] Add email password sign in
- [ ] Document
- [ ] Submit PR to NextAuth documentation with fixes

# Supplemental Information

No files are named in the issue. Start by locating the existing NextAuth setup and any auth wrapper/component for Google/Discord sign-in, then inspect where the FaunaDB adapter is wired. Extend that same flow for the remaining email/password login task and any required setup notes. Validate with the repo’s auth run path or related checks, and mark done only when email/password login works and the task’s docs updates are in place.

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