Add Nix flake configuration

modules/shell/fzf.nix

@@ -0,0 +1,21 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+with lib.my;
+let cfg = config.modules.shell.fzf;
+in {
+  options.modules.shell.fzf = {
+    enable = mkBoolOpt false;
+  };
+
+  config = mkIf cfg.enable {
+    home.packages = with pkgs; [
+      bind
+    ];
+    home.programs.fzf = {
+      enable = true;
+      enableZshIntegration = true;
+      defaultCommand = "fd --type f --hidden --follow --exclude .git";
+    };
+  };
+}