Added a `.keep` file to the `git` directory to ensure its presence in the user's home structure. This aligns with the convention of maintaining stub files for empty directories.
The user's extraGroups in the NixOS module now contains 'wheel' by default. This change provides the user with more privileges. Consequently, 'wheel' has been removed from the SGX-Attic's 'user.extraGroups' as it became redundant.