chore: drop redundant packages and options

- packages.nix is the baseline: drop neovim (nixvim), nvd, sof-firmware (enableAllFirmware), qtmultimedia (v4 leftover); vial moves to vial.nix, wl-clipboard to noctalia.nix, claude-code becomes a plain package here
- drop packages and options already provided elsewhere: noctalia (home-manager), gnupg/pinentry-qt (agent), gtk/qt themes, sddm Theme.Current, zsh plugins (home-manager), group = users, empty firewall lists
- single-package lists without `with pkgs;`, steam package inside its block

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

modules/nixos/networking.nix

@@ -1,20 +1,12 @@
 { pkgs, ... }:
 
 {
-  # user networkmanager
   networking.networkmanager.enable = true;
 
-  # firewall default configs
-  networking.firewall.allowedTCPPorts = [ ];
-  networking.firewall.allowedUDPPorts = [ ];
-
-  # enable wifi firmware
+  # wifi firmware and bluetooth
   hardware.enableAllFirmware = true;
-
-  # enable bluetooth
   hardware.bluetooth.enable = true;
 
-  # Add network-related packages
   environment.systemPackages = with pkgs; [
     wireguard-tools
     update-systemd-resolved