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.

system/boot.nix

@@ -0,0 +1,6 @@
+{ ... }:
+
+{
+  boot.loader.systemd-boot.enable = true;
+  boot.loader.efi.canTouchEfiVariables = true;
+}

system/display-manager.nix

@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  services.displayManager.ly.enable = true;
+}

system/fonts.nix

@@ -0,0 +1,7 @@
+{ pkgs, ... }:
+
+{
+  fonts.packages = with pkgs; [
+    jetbrains-mono
+  ];
+}

system/locale.nix

@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  time.timeZone = "Europe/Berlin";
+}

system/networking.nix

@@ -0,0 +1,6 @@
+{ ... }:
+
+{
+  networking.hostName = "hivebrain";
+  networking.networkmanager.enable = true;
+}

system/nix.nix

@@ -0,0 +1,6 @@
+{ ... }:
+
+{
+  nix.settings.experimental-features = [ "nix-command" "flakes" ];
+  nixpkgs.config.allowUnfree = true;
+}

system/packages.nix

@@ -0,0 +1,10 @@
+{ pkgs, ... }:
+
+{
+  environment.systemPackages = with pkgs; [
+    vim
+    wget
+    btop
+    jq
+  ];
+}

system/picom.nix

@@ -0,0 +1,9 @@
+{ ... }:
+
+{
+  services.picom = {
+    enable = true;
+    backend = "xrender";
+    fade = true;
+  };
+}

system/programs.nix

@@ -0,0 +1,7 @@
+{ ... }:
+
+{
+  programs.firefox.enable = true;
+  programs.zsh.enable = true;
+  programs.nix-ld.enable = true;
+}

system/ssh.nix

@@ -0,0 +1,5 @@
+{ ... }:
+
+{
+  services.openssh.enable = true;
+}

system/users.nix

@@ -0,0 +1,12 @@
+{ pkgs, ... }:
+
+{
+  users.users.marvin = {
+    isNormalUser = true;
+    extraGroups = [ "wheel" ];
+    shell = pkgs.zsh;
+    packages = with pkgs; [
+      tree
+    ];
+  };
+}

system/xserver.nix

@@ -0,0 +1,28 @@
+{ ... }:
+
+{
+  services.xserver = {
+    enable = true;
+    autoRepeatDelay = 200;
+    autoRepeatInterval = 35;
+    windowManager.qtile.enable = true;
+    displayManager.sessionCommands = ''
+      xwallpaper --zoom ~/nixos-dotfiles/Pictures/NixOsWallpaper.png
+    '';
+    xrandrHeads = [
+      {
+        output = "HDMI-1";
+        monitorConfig = ''
+          Option "Position" "0 0"
+        '';
+      }
+      {
+        output = "DP-1";
+        primary = true;
+        monitorConfig = ''
+          Option "Position" "1920 0"
+        '';
+      }
+    ];
+  };
+}