refactor: fully rebase to nixpkgs-unstable rather than fixed release with backports

hosts/nero/configuration.nix

@@ -3,16 +3,6 @@
   inputs,
   ...
 }:
-let
-  unstable = import inputs.nixpkgs-unstable {
-    system = pkgs.stdenv.hostPlatform.system;
-    config.allowUnfree = true;
-  };
-
-  wivrn-overlay = _final: _prev: {
-    inherit (unstable) wivrn;
-  };
-in
 {
   imports = [
     ../shared/nixos-pc.nix
@@ -21,7 +11,6 @@ in
   ];
 
   nixpkgs.overlays = [
-    wivrn-overlay
     inputs.millennium.overlays.default
     inputs.cheatengine.overlays.default
   ];
@@ -133,14 +122,13 @@ in
       cheatengine
       lsfg-vk
       lsfg-vk-ui
-
-      unstable.qbittorrent
-      unstable.aseprite
+      qbittorrent
+      aseprite
 
       inputs.scopebuddy.packages.${pkgs.stdenv.hostPlatform.system}.default
       inputs.xivlauncher-rb.packages.${pkgs.stdenv.hostPlatform.system}.default
 
-      (callPackage ../../packages/aseprite-thumbnailer-kde/package.nix { inherit unstable; })
+      (callPackage ../../packages/aseprite-thumbnailer-kde/package.nix { })
       (callPackage ../../packages/undertale-mod-tool/package.nix { })
     ];
   };