feat: finish transition to flake-parts

nix/pkgs.nix

@@ -0,0 +1,37 @@
+{inputs, ...}: {
+  imports = [
+    (
+      {
+        lib,
+        flake-parts-lib,
+        ...
+      }:
+        flake-parts-lib.mkTransposedPerSystemModule {
+          name = "pkgs";
+          file = ./pkgs.nix;
+          option = lib.mkOption {
+            type = lib.types.unspecified;
+          };
+        }
+    )
+  ];
+
+  perSystem = {
+    pkgs,
+    system,
+    ...
+  }: {
+    _module.args.pkgs = import inputs.nixpkgs {
+      inherit system;
+      config.allowUnfree = true;
+      overlays =
+        import ../pkgs/default.nix
+        ++ [
+          inputs.nix-topology.overlays.default
+          inputs.nixos-extra-modules.overlays.default
+        ];
+    };
+
+    inherit pkgs;
+  };
+}