Fix: use nixpkgs.lib.nixosSystem; add minimal config

configuration.nix

@@ -1 +1,26 @@
-# placeholder
+{ config, pkgs, ... }:
+
+{
+  imports = [ ./hardware ];     # bindet die auto-generierte HW-Datei ein
+
+  boot.loader.systemd-boot.enable = true;
+  boot.loader.efi.canTouchEfiVariables = true;
+
+  networking.hostName = "nix-nas";
+
+  users.users.nicole = {
+    isNormalUser = true;
+    extraGroups = [ "wheel" "docker" "libvirtd" ];
+    openssh.authorizedKeys.keys = [
+      "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIGAsiKDWCwyf1usprg3K6Zk0xE9S4DX6+Bc4+nIOZGmf drezil@Manticore"
+    ];
+  };
+
+  services.openssh.enable = true;
+  services.zfs.autoScrub.enable = true;   # Snapshots & Details kommen später
+
+  # Wir pinnen den Kernel, bis ZFS 2.3.x für 6.13 bereit ist
+  boot.kernelPackages = pkgs.linuxPackages_6_12;
+
+  environment.systemPackages = with pkgs; [ git vim ];
+}

flake.nix

@@ -1,18 +1,23 @@
 {
   description = "NAS on NixOS – root on ZFS";
 
-  inputs.nixpkgs.url = "github:NixOS/nixpkgs/release-25.05";
+  inputs = {
+    # stabiler Release-Zweig
+    nixpkgs.url        = "github:NixOS/nixpkgs/nixos-25.05";
+    # optional: Hardware-Tuning (z. B. SSD-Defaults)
+    nixos-hardware.url = "github:NixOS/nixos-hardware";
+  };
 
-  outputs = { self, nixpkgs }:
+  outputs = { self, nixpkgs, nixos-hardware, ... }@inputs:
   let
     system = "x86_64-linux";
-    pkgs   = import nixpkgs { inherit system; };
   in {
-    nixosConfigurations.host = pkgs.lib.nixosSystem {
-      inherit system;
+    nixosConfigurations.host = nixpkgs.lib.nixosSystem {
+      inherit system;                     # ← Pflichtfeld
       modules = [
-        ./hardware
-        ./configuration
+        ./hardware                        # dein generiertes hardware-configuration.nix
+        ./configuration.nix               # deine eigentliche Config
+        nixos-hardware.nixosModules.common-pc-ssd
       ];
     };
   };