Add devenv registry

flake.nix

@@ -22,6 +22,12 @@
       url = "github:hyprwm/Hyprpaper";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+
+    # devenv
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs = inputs @ { self, nixpkgs, ... }: {
@@ -33,6 +39,7 @@
         modules = [
           (import ./modules/impurity.nix self)
           ./modules/preserve-system.nix
+          ./modules/devenv
           ./modules/overlay-pkgs
           ./modules/core
           ./modules/system.nix