feat: Convert to a multi-host flake

flake.nix

@@ -1,23 +1,32 @@
-# /etc/nixos/flake.nix
 {
-  description = "Framework Desktop with Strix Halo";
+  description = "NixOS configurations for crossbox and anvil";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     strix-halo.url = "github:hellas-ai/nix-strix-halo";
   };
 
-  outputs = { self, nixpkgs, strix-halo, ... }: {
-    nixosConfigurations.crossbox = nixpkgs.lib.nixosSystem {
-      system = "x86_64-linux";
-      modules = [
-        ./configuration.nix
-        
-        ({ pkgs, ... }: {
-          # Apply Strix Halo overlay
-          nixpkgs.overlays = [ strix-halo.overlays.default ];
-        })
-      ];
+  outputs = { self, nixpkgs, strix-halo, ... }:
+  let
+    mkHost = { hostDir, extraModules ? [], overlays ? [] }:
+      nixpkgs.lib.nixosSystem {
+        system = "x86_64-linux";
+        modules = [
+          ./configuration.nix
+          hostDir
+          ({ ... }: { nixpkgs.overlays = overlays; })
+        ] ++ extraModules;
+      };
+  in {
+    nixosConfigurations.crossbox = mkHost {
+      hostDir = ./hosts/crossbox;
+      overlays = [ strix-halo.overlays.default ];
+      extraModules = [ ./sdr.nix ./syncthing.nix ];
+    };
+
+    nixosConfigurations.anvil = mkHost {
+      hostDir = ./hosts/anvil;
+      extraModules = [ ./sdr.nix ./syncthing.nix ];
     };
   };
-}
+}