add single-file NixOS aspects

Standalone NixOS modules: ai, bluetooth, dev, fwupd, libvirtd,
networkmanager, podman

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

aspects/dev.nix

@@ -0,0 +1,19 @@
+{ ... }:
+{
+  flake.modules.nixos.dev = { config, lib, pkgs, ... }: {
+    environment.systemPackages = with pkgs; [
+      android-tools
+      bat
+      lazygit
+      fd
+      fzf
+      glow
+      nixfmt
+      nix-init
+      nix-output-monitor
+      ripgrep
+    ];
+
+    users.users.user.extraGroups = [ "adbusers" ];
+  };
+}