initial nixos flake setup

system/overlays.nix

@@ -0,0 +1,19 @@
+{ inputs, ... }:
+
+{
+  nixpkgs.overlays = [
+    (final: prev:
+      let
+        unstable-pkgs = import inputs.nixpkgs-unstable {
+          inherit (prev) system;
+          config.allowUnfree = true;
+          config.allowUnsupportedSystem = true;
+        };
+      in
+      {
+        inherit (unstable-pkgs) ollama kdePackages sddm;
+        unstable = unstable-pkgs;
+      }
+    )
+  ];
+}