fixed gc optimise and channels

hosts/base/default.nix

@@ -152,6 +152,16 @@
   nix = {
     nixPath = [ "nixpkgs=${inputs.nixpkgs.outPath}" ];
     registry.nixpkgs.flake = inputs.nixpkgs;
+    channel.enable = false;
+    optimise = {
+      automatic = true;
+      dates = [ "weekly" ];
+    };
+    gc = {
+      automatic = true;
+      dates = "weekly";
+      options = "--delete-older-than 14d";
+    };
   };
 
   home-manager = {
@@ -173,5 +183,4 @@
   # Before changing this value read the documentation for this option
   # (e.g. man configuration.nix or on https://nixos.org/nixos/options.html).
   system.stateVersion = "24.05"; # Did you read the comment?
-
 }