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.nix

@@ -1,76 +1,17 @@
-{ config, pkgs, lib, ... }:
+{ ... }:
 
 {
-	home.username = "marvin";
-	home.homeDirectory = "/home/marvin";
-	home.stateVersion = "26.05";
-	programs = {
-    yazi.enable = true;
+  imports = [
+    ./home/zsh.nix
+    ./home/git.nix
+    ./home/rofi.nix
+    ./home/yazi.nix
+    ./home/packages.nix
+    ./home/symlinks.nix
+    ./home/fonts.nix
+  ];
 
-		git = {
-      enable = true;
-      settings.user = {
-        name = "MDietermann";
-        email = "marvin.dietermann@hive-brain.de";
-      };
-    };
-
-    rofi = {
-      enable = true;
-      theme = "arthur";
-      font = "sans-serif";
-      package = pkgs.rofi;
-      modes = [
-        "drun"
-        "run"
-        "window"
-        "ssh"
-      ];
-      extraConfig = {
-        show-icons = true;
-      };
-    };
-
-		zsh = {
-			enable = true;
-      enableCompletion = true;
-      autosuggestion.enable = true;
-      syntaxHighlighting.enable = true;
-
-      history.size = 10000;
-      history.ignoreAllDups = true;
-      history.path = "$HOME/.zsh_history";
-
-      oh-my-zsh = {
-        enable = true;
-        plugins = [ "git" "sudo" ];
-        theme = "aussiegeek";
-      };
-
-			shellAliases = {
-				btw = "echo I use NixOS";
-        reload-nixos = "sudo nixos-rebuild switch --flake ~/nixos-dotfiles#hivebrain";
-			};
-		};
-	};
-
-	home.file = lib.mapAttrs'
-		(name: _: lib.nameValuePair ".config/${name}" {
-			source = config.lib.file.mkOutOfStoreSymlink
-				"${config.home.homeDirectory}/nixos-dotfiles/config/${name}";
-		})
-		(lib.filterAttrs (_: type: type == "directory") (builtins.readDir ./config));
-
-	home.packages = with pkgs; [
-		neovim
-		ripgrep
-		nil
-		nixpkgs-fmt
-		nodejs
-		gcc
-    rofi
-    xwallpaper
-    steam
-    unzip
-	];
+  home.username = "marvin";
+  home.homeDirectory = "/home/marvin";
+  home.stateVersion = "26.05";
 }