refactor(docker): rootless only

Drops the root daemon and the root-equivalent docker group; the daemon settings now apply to the rootless daemon. compose ships with the docker package.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

modules/nixos/docker.nix

@@ -1,12 +1,8 @@
-{ pkgs, ... }:
-
 {
-  # add docker group to user
-  users.users.aaron.extraGroups = [ "docker" ];
-
-  virtualisation.docker = {
+  # rootless only: no root daemon and no root-equivalent docker group
+  virtualisation.docker.rootless = {
     enable = true;
-    # Customize Docker daemon settings
+    setSocketVariable = true;
     daemon.settings = {
       dns = [
         "1.1.1.1"
@@ -14,16 +10,6 @@
       ];
       log-driver = "journald";
       registry-mirrors = [ "https://mirror.gcr.io" ];
-      storage-driver = "overlay2";
     };
-    # Use the rootless mode
-    rootless = {
-      enable = true;
-      setSocketVariable = true;
-    };
-    # Install docker-compose
-    extraPackages = with pkgs; [
-      docker-compose
-    ];
   };
 }