Split configuration.nix and home.nix into per-domain modules

Break the two monolithic files into focused modules under system/
and home/ so each concern (boot, networking, xserver, picom, zsh,
git, rofi, etc.) lives in its own file. Clean up duplicates: drop
rofi from home.packages since programs.rofi.enable already installs
it, and move user-only apps (alacritty, obsidian, claude-code) from
environment.systemPackages to home.packages. Remove commented-out
boilerplate carried over from the install template.

home/fonts.nix

@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  fonts.fontconfig.enable = true;
+}

home/git.nix

@@ -0,0 +1,11 @@
+{ ... }:
+
+{
+  programs.git = {
+    enable = true;
+    settings.user = {
+      name = "MDietermann";
+      email = "marvin.dietermann@hive-brain.de";
+    };
+  };
+}

home/packages.nix

@@ -0,0 +1,21 @@
+{ pkgs, ... }:
+
+{
+  home.packages = with pkgs; [
+    alacritty
+    claude-code
+    gcc
+    lua-language-server
+    neovim
+    nerd-fonts.jetbrains-mono
+    nil
+    nixpkgs-fmt
+    nodejs
+    obsidian
+    ripgrep
+    rustup
+    steam
+    unzip
+    xwallpaper
+  ];
+}

home/rofi.nix

@@ -0,0 +1,19 @@
+{ pkgs, ... }:
+
+{
+  programs.rofi = {
+    enable = true;
+    theme = "arthur";
+    font = "sans-serif";
+    package = pkgs.rofi;
+    modes = [
+      "drun"
+      "run"
+      "window"
+      "ssh"
+    ];
+    extraConfig = {
+      show-icons = true;
+    };
+  };
+}

home/symlinks.nix

@@ -0,0 +1,10 @@
+{ config, lib, ... }:
+
+{
+  home.file = lib.mapAttrs'
+    (name: _: lib.nameValuePair ".config/${name}" {
+      source = config.lib.file.mkOutOfStoreSymlink
+        "${config.home.homeDirectory}/nixos-dotfiles/config/${name}";
+    })
+    (lib.filterAttrs (_: type: type == "directory") (builtins.readDir ../config));
+}

home/yazi.nix

@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  programs.yazi.enable = true;
+}

home/zsh.nix

@@ -0,0 +1,25 @@
+{ ... }:
+
+{
+  programs.zsh = {
+    enable = true;
+    enableCompletion = true;
+    autosuggestion.enable = true;
+    syntaxHighlighting.enable = true;
+
+    history.size = 10000;
+    history.ignoreAllDups = true;
+    history.path = "$HOME/.zsh_history";
+
+    oh-my-zsh = {
+      enable = true;
+      plugins = [ "git" "sudo" ];
+      theme = "aussiegeek";
+    };
+
+    shellAliases = {
+      btw = "echo I use NixOS";
+      reload-nixos = "sudo nixos-rebuild switch --flake ~/nixos-dotfiles#hivebrain";
+    };
+  };
+}