Add garbage-collect for home-manager

homes/julian/global/default.nix

@@ -35,6 +35,13 @@
 
   # systemd.user.startServices = "sd-switch"; # TODO: what is this
 
+  # Expire old hm generations
+  hm-expire = {
+    enable = true;
+    dates = "weekly";
+    expire = "-30 days";
+  };
+
   programs = {
     home-manager.enable = true;
     git.enable = true;

homes/julian/hm-standalone-config.nix

@@ -39,6 +39,20 @@
       "ca-derivations"
     ];
 
+    # Expire old hm generations
+    hm-expire = {
+      enable = true;
+      dates = "weekly";
+      expire = "-30 days";
+    };
+    # Remove unused packets
+    services.nix-gc = {
+      enable = true;
+      automatic = true;
+      frequency = "weekly";
+      persistent = true;
+    };
+
     # nix.settings. # warn-dirty = false; # TODO: do I want this
     #
     # Ensure we can still build when missing-server is not accessible