feat: implement the managed Hyprland desktop with Kitty and stable updates

flake.nix

@@ -2,11 +2,11 @@
   description = "Development host";
 
   inputs = {
-    # Reviewed stable 26.05 snapshot; update deliberately, not at boot/login.
-    nixpkgs.url = "github:NixOS/nixpkgs/a5cc6f2c37bf518436dc8d1c288ccd0c43c2f4c4";
+    # Release branches may advance; flake.lock records every exact snapshot.
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-26.05";
 
     home-manager = {
-      url = "github:nix-community/home-manager/65258d5c65a250189fde2e35f490d15e064c4c62";
+      url = "github:nix-community/home-manager/release-26.05";
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
@@ -28,5 +28,36 @@
       };
 
       formatter.x86_64-linux = nixpkgs.legacyPackages.x86_64-linux.nixfmt;
+
+      nixosModules = {
+        desktop = ./desktop.nix;
+        apps = ./apps.nix;
+        tools = ./tools.nix;
+        network = ./network.nix;
+        workstation = ./workstation.nix;
+        nvidia = ./nvidia.nix;
+      };
+      checks.x86_64-linux =
+        let
+          pkgs = nixpkgs.legacyPackages.x86_64-linux;
+        in
+        {
+          desktop = import ./desktop-test.nix { inherit inputs pkgs; };
+          updates =
+            pkgs.runCommand "update-workflow-check"
+              {
+                nativeBuildInputs = with pkgs; [
+                  python3
+                  git
+                  bash
+                  coreutils
+                  util-linux
+                ];
+              }
+              ''
+                python ${./update-test.py} ${./update-system.sh}
+                touch "$out"
+              '';
+        };
     };
 }