Add Nix flake configuration

modules/shell/zsh.nix

@@ -0,0 +1,35 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+with lib.my;
+let cfg = config.modules.shell.zsh;
+in {
+  options.modules.shell.zsh = {
+    enable = mkBoolOpt false;
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = with pkgs; [
+      zsh-autosuggestions
+      zsh-fast-syntax-highlighting
+      zsh-history-substring-search
+    ];
+
+    home.programs.zsh = {
+      enable = true;
+      enableCompletion = true;
+      shellAliases = {
+        cp = "cp -iv";
+        mv = "mv -iv";
+        rm = "rm -v";
+        mkdir = "mkdir -v";
+        ls = "ls -h --color=auto --group-directories-first";
+        e = "nvim";
+        f = "nnn";
+        g = "git";
+        n = "nnn";
+        v = "nvim";
+      };
+    };
+  };
+}