Allow Elle to create and edit user groups

Enable Elle to create, edit, and manage user groups in Aha! Roadmaps.

This should include the ability to:

• Create new user groups

• Rename existing user groups

• Add and remove users from groups

• Update group permissions or roles where supported

• Understand the distinction between teams, approval groups, and other group-like account structures so Elle can take the correct action

This would help administrators manage account access and organization directly through Elle instead of navigating account settings manually.