feat: nas add audiobookshelf

hosts/nas/modules/audiobookshelf.nix

@@ -0,0 +1,16 @@
+{ config, lib, pkgs, ... }: {
+  # Audiobookshelf user with jellyfin and pyload groups for multimedia access
+  users.users.audiobookshelf = {
+    isSystemUser = true;
+    group = "audiobookshelf";
+    extraGroups = [ "jellyfin" "pyload" ];
+  };
+  users.groups.audiobookshelf = {};
+
+  services.audiobookshelf = {
+    enable = true;
+    openFirewall = true;  # Opens default port 13378
+    host = "0.0.0.0";     # Listen on all interfaces
+    port = 13378;
+  };
+}