Add home-manager config for sonja from ~/.config/home-manager

Moves home-manager configuration into the flake under home/sonja/,
integrating git, GPG agent, and package config. Fixes deprecated
home-manager options and removes nixpkgs.config override incompatible
with useGlobalPkgs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

home/sonja/home.nix

@@ -0,0 +1,29 @@
+{ pkgs, ... }:
+
+{
+  imports = [
+    ./gpg-agent.nix
+    ./git.nix
+  ];
+
+  custom.pgp.enable = true;
+
+  home.packages = [
+    pkgs.librewolf
+    pkgs.zsh
+    pkgs.neovim
+    pkgs.nmap
+    pkgs.alacritty
+    pkgs.tmux
+    pkgs.git
+    pkgs.uv
+    pkgs.discord
+    pkgs.steam-unwrapped
+    pkgs.steam-tui
+    pkgs.supersonic
+    pkgs.fzf
+    pkgs.claude-code
+  ];
+
+  home.stateVersion = "25.11";
+}