feat(pikachu): add Fabric Minecraft guest

flake.nix

@@ -19,6 +19,12 @@
     # Installs Flatpak applications declaratively.
     nix-flatpak.url = "github:gmodena/nix-flatpak/?ref=v0.7.0";
 
+    # Packages reproducible Minecraft servers and modpacks.
+    nix-minecraft = {
+      url = "github:Infinidoge/nix-minecraft";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     # Provides signed AMO extensions pinned by version and hash.
     firefox-addons = {
       url = "gitlab:rycee/nur-expressions?dir=pkgs/firefox-addons";