Extract flake modules

flake-modules/packages.nix

@@ -0,0 +1,21 @@
+{ inputs, self, ... }:
+
+{
+  perSystem =
+    { pkgs, system, ... }:
+    let
+      # TODO: refactor to use inputs' or similar.
+      nixvim = inputs.nixvim.legacyPackages.${system}.makeNixvimWithModule {
+        inherit pkgs;
+
+        module = import "${self}/modules/home-manager/coding/neovim/config";
+      };
+    in
+    {
+      packages = {
+        inherit nixvim;
+
+        default = pkgs.mkShell { buildInputs = with pkgs; [ just ]; };
+      };
+    };
+}