refactor(flake): rename custom package overlay

src/dotfiles/default.nix

@@ -35,7 +35,7 @@ let
   };
   modules.imports = [
     {
-      nixpkgs.overlays = [ self.overlays.default ];
+      nixpkgs.overlays = [ self.overlays.custom ];
     }
   ]
   ++ util.collectNixFiles (root + "/modules");

src/flake/default.nix

@@ -6,7 +6,7 @@
   system,
 }:
 {
-  overlays.default = final: _prev: {
+  overlays.custom = final: _prev: {
     alexion = import ./packages {
       pkgs = final;
       inherit root;
@@ -16,7 +16,7 @@
   packages.${system} =
     (import inputs.nixpkgs {
       inherit system;
-      overlays = [ self.overlays.default ];
+      overlays = [ self.overlays.custom ];
     }).alexion;
 
   nixosConfigurations = import ../dotfiles {