treewide: add devShell

flake.nix

@@ -38,6 +38,7 @@
     flake-parts.lib.mkFlake { inherit inputs; } {
       imports = [
         ./nixos
+        ./shells
       ];
 
       perSystem =

shells/default.nix

@@ -0,0 +1,27 @@
+{ inputs, ... }:
+{
+  perSystem =
+    { pkgs, ... }:
+    {
+      devShells.default = pkgs.mkShell {
+        name = "configuration.nix";
+        packages = with pkgs; [
+          bat
+          cachix
+          deadnix
+          delta
+          git
+          inputs.agenix.packages.${stdenv.hostPlatform.system}.default
+          jujutsu
+          neovim
+          nix-output-monitor
+          nixfmt
+          npins
+          parted
+          smartmontools
+          statix
+          tmux
+        ];
+      };
+    };
+}