feat: implement modular foundation and core system services

- Update flake.nix with 25.11 release and core inputs
- Add dedicated modules for audio (Pipewire), bluetooth, and networking
- Update GEMINI.md with the new Modular Merging Architecture blueprint
- Configure graphical installer ISO and test VM outputs

bin/nomarchy-install-steam

@@ -1,9 +1,23 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
-# Install and launch Steam after first letting the user pick the correct grahics card drivers.
+# Configure Steam declaratively for NixOS
 
-set -e
+FEATURE_FILE="/etc/nixos/nomarchy-features/steam.nix"
 
-echo "Now pick dependencies matching your graphics card"
-sudo pacman -S steam
-setsid gtk-launch steam >/dev/null 2>&1 &
+if [ -f "$FEATURE_FILE" ]; then
+    echo "Steam is already configured in $FEATURE_FILE"
+    exit 0
+fi
+
+sudo mkdir -p "/etc/nixos/nomarchy-features"
+cat <<EOF | sudo tee "$FEATURE_FILE" > /dev/null
+{ config, pkgs, ... }:
+{
+  programs.steam.enable = true;
+  hardware.graphics.enable32Bit = true; # Needed for many games
+}
+EOF
+
+echo "Created $FEATURE_FILE."
+echo "IMPORTANT: To finish enabling Steam, add './nomarchy-features/steam.nix' to your imports list in /etc/nixos/system.nix or /etc/nixos/flake.nix,"
+echo "then run 'sys-update'."