- Refactor shared `user` role to use `user_key` exclusively (remove user_name)
- Resolve system username, home, group, and ownership via users[user_key]
- Update SSH authorized_keys handling to read from users[user_key]
- Adjust documentation to clearly describe user_key-based SPOT model
- Migrate all calling roles (administrator, backup, root) to pass user_key
- Introduce new `user-workstation` role with dedicated README, vars, tasks, and metadata
- Add workstation stage integration to ensure workstation user setup runs explicitly
- Ensure consistent variable naming (lowercase internals, uppercase constants)
- Improve robustness and clarity of user management across all roles
https://chatgpt.com/share/695ea93e-3fa0-800f-b848-ec2ced2a8291
