simplify and inline a lot of home-manager stuff

home-manager/no-gui.nix

@@ -4,6 +4,7 @@
   lib,
   homeDirectory,
   config,
+  username,
   ...
 }:
 let
@@ -48,6 +49,20 @@ in
   imports = [
     ./progs/fish.nix
     ./progs/helix.nix
+    inputs.agenix.homeManagerModules.age
+    (
+      { ... }:
+      {
+        nixpkgs.overlays = [
+          inputs.rust-overlay.overlays.default
+        ];
+
+        # home-manager stuff
+        home = {
+          inherit username homeDirectory;
+        };
+      }
+    )
   ];
 
   home.stateVersion = "24.11";