prep: setup sops demo for otf

configurations/nixos/tofu/default.nix

@@ -1,6 +1,11 @@
 # See /modules/nixos/* for actual settings
 # This file is just *top-level* configuration.
-{ flake, modulesPath, ... }:
+{
+  flake,
+  modulesPath,
+  config,
+  ...
+}:
 
 let
   inherit (flake) inputs;
@@ -15,6 +20,7 @@ in
     tty-ips.enable = true;
     otf = {
       enable = true;
+      environmentFile = config.sops.secrets.otfenv.path;
     };
   };
   networking = {