Configure for atlas/pinj and add Wayland session variables

- Rename hosts/hostname/ to hosts/atlas/
- Replace all <hostname> placeholders with 'atlas'
- Replace all <username> placeholders with 'pinj'
- Set timezone to Europe/Rome (with TODO note to change if needed)
- Set locale to en_US.UTF-8
- Add Wayland session variables (QT_QPA_PLATFORM, MOZ_ENABLE_WAYLAND,
  NIXOS_OZONE_WL) for proper app integration
- Remove placeholder comments that are no longer needed

https://claude.ai/code/session_01UAdmEkSeh9NGPfjRfViLWY

modules/dev.nix

@@ -22,10 +22,9 @@
     };
   };
 
-  # IMPORTANT: Replace <username> with actual username
   # NOTE: After first enabling/applying this dev profile, you must log out and
   # log back in (or reboot) for the docker group membership to take effect.
-  users.users.<username>.extraGroups = [ "docker" ];
+  users.users.pinj.extraGroups = [ "docker" ];
 
   # --------------------------------------------------------------------------
   # DEVELOPMENT TOOLS
@@ -35,8 +34,7 @@
     nix-direnv.enable = true;  # Caches nix shells
   };
 
-  # IMPORTANT: Replace <username> with actual username
-  users.users.<username>.packages = with pkgs; [
+  users.users.pinj.packages = with pkgs; [
     # -- Git --
     lazygit
     gh              # GitHub CLI