refactor ai stuff

modules/apps/sys/ai.nix

@@ -0,0 +1,12 @@
+{ ... }: {
+  flake.nixosModules.apps-sys-ai = { pkgs, ... }: {
+    environment.systemPackages = with pkgs; [
+      opencode
+    ];
+    services.ollama = {
+      enable = true;
+      package = pkgs.ollama-rocm;
+      loadModels = [ "gpt-oss:20b" ];
+    };
+  };
+}