Add API route docs, user tokens, test typing fixes, and collaborator API cleanup

Added

• API route documentation generated from the API, available at /apidocs

• User tokens that authenticate as a user, similar to book tokens

  • Useful for automating group additions or user invites

Fixed

• Tests are now type-checked
• Fixed various typing issues in the test suite

Cleanup

• Moved collaborator client API to the api folder to centralize fetch logic