❄️ Add Nix shell

flake.nix

@@ -0,0 +1,36 @@
+{
+  description = "martials.no Development environment";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.05";
+  };
+
+  outputs = { nixpkgs, ... }:
+    let
+      system = "x86_64-linux";
+    in
+    {
+      devShells.${system}.default =
+        let
+          pkgs = import nixpkgs {
+            inherit system;
+          };
+        in
+        pkgs.mkShell {
+          packages = with pkgs; [
+            git
+          ] ++ [
+            # Node
+            nodejs_22
+            pnpm
+          ] ++ [
+            nodePackages.prettier
+          ];
+
+          shellHook = ''
+            pnpm install
+            fish
+          '';
+        };
+    };
+}