Add Steam Deck (nix-deck) configuration with Jovian-NixOS and remote building

- Add Jovian-NixOS integration for Steam Deck hardware support
- Create nix-deck machine configuration with SteamOS role
- Add jovian-compat.nix for NixOS 25.05 compatibility (remove in 25.11+)
- Create remote-build role for distributed builds
- Configure zix790prors as build host
- Configure nix-book and nix-deck to use remote builder with fallback
- Add comprehensive setup documentation

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

flake.nix

@@ -26,6 +26,11 @@
       url = "git+https://git.johnogle.info/johno/google-cookie-retrieval.git";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
+    jovian = {
+      url = "github:Jovian-Experiments/Jovian-NixOS";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs = { self, nixpkgs, nixpkgs-unstable, nixos-wsl, ... } @ inputs: let
@@ -33,6 +38,8 @@
       ./roles
     ] ++ [
       inputs.home-manager.nixosModules.home-manager
+      ./roles/jovian-compat.nix  # Compatibility shim for Jovian on stable NixOS
+      inputs.jovian.nixosModules.jovian
       {
         nixpkgs.overlays = [
           (final: prev: {
@@ -142,6 +149,18 @@
       ];
     };
 
+    # Steam Deck configuration
+    nixosConfigurations.nix-deck = nixpkgs.lib.nixosSystem rec {
+      system = "x86_64-linux";
+      modules = nixosModules ++ [
+        ./machines/nix-deck/configuration.nix
+        {
+          home-manager.users.johno = import ./home/home-desktop.nix;
+          home-manager.extraSpecialArgs = { inherit system; };
+        }
+      ];
+    };
+
     # Darwin/macOS configurations
     darwinConfigurations."blkfv4yf49kt7" = inputs.nix-darwin.lib.darwinSystem rec {
       system = "aarch64-darwin";