flake: pass inputs as special argument to modules

flake.nix

@@ -45,8 +45,9 @@
   outputs = { home-manager, nixpkgs, agenix, snm, ... }@inputs: {
     nixosConfigurations."thrall" = nixpkgs.lib.nixosSystem {
       system = "x86_64-linux";
+      specialArgs = { inherit inputs; };
       modules = [
-        ({
+        ({ inputs, ... }: {
           nixpkgs = {
             config.allowUnfree = true;
             overlays = with inputs; [ emacs.overlay ];