Upgrade NixOS to 25.11 and fix Jovian module organization

- Update flake inputs from 25.05 to 25.11 (nixpkgs, home-manager, nix-darwin)
- Remove Jovian compatibility shim that's no longer needed
- Move SteamOS configuration to only import in nix-deck machine
- Fixes jovian module not found error during nixos-rebuild

flake.nix

@@ -2,17 +2,17 @@
   description = "A very basic flake";
 
   inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.05";
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-25.11";
     nixpkgs-unstable.url = "github:nixos/nixpkgs/nixos-unstable";
     nixos-wsl.url = "github:nix-community/NixOS-WSL/main";
     
     nix-darwin = {
-      url = "github:nix-darwin/nix-darwin/nix-darwin-25.05";
+      url = "github:nix-darwin/nix-darwin/nix-darwin-25.11";
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
     home-manager = {
-      url = "github:nix-community/home-manager/release-25.05";
+      url = "github:nix-community/home-manager/release-25.11";
       inputs.nixpkgs.follows = "nixpkgs";
     };
 
@@ -48,7 +48,6 @@
     nixosModules = [
       ./roles
     ] ++ [
-      ./roles/jovian-compat.nix
       inputs.home-manager.nixosModules.home-manager
       {
         nixpkgs.overlays = [