Fix nvf markdown formatter, tuigreet build, and Hyprland breakage

nvf's markdown formatter only accepts prettier (not prettierd); tuigreet's
NotAShelf fork is archived and its build now fails, so switch to nixpkgs'
package; and the hyprland flake input tracked an unreleased dev branch that
had dropped .conf support, breaking config loading, so switch to nixpkgs'
stable Hyprland release instead.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

nixos/hyprland.nix

@@ -1,14 +1,7 @@
 # Hyprland is a dynamic tiling Wayland compositor.
-{
-  inputs,
-  pkgs,
-  ...
-}: {
+{...}: {
   programs.hyprland = {
     enable = true;
     withUWSM = true;
-    package = inputs.hyprland.packages."${pkgs.stdenv.hostPlatform.system}".hyprland;
-    portalPackage =
-      inputs.hyprland.packages.${pkgs.stdenv.hostPlatform.system}.xdg-desktop-portal-hyprland;
   };
 }

nixos/tuigreet.nix

@@ -6,7 +6,7 @@
   ...
 }: let
   c = config.lib.stylix.colors;
-  tuigreet = inputs.notashelf-tuigreet.packages.${pkgs.stdenv.hostPlatform.system}.default;
+  tuigreet = pkgs.tuigreet;
 
   theme = lib.concatStringsSep ";" [
     "border=#${c.base0D}"