fix: 修复首次 darwin-rebuild 的构建错误

- nix.enable=false 兼容 Determinate Nix (macOS)
- 禁用 catppuccin.nvim (require check 失败)
- fl-clash 用完整 tap 路径放入 casks
- 修复 SSH/git 废弃选项警告
- 更新 flake.lock

modules/darwin/default.nix

@@ -63,7 +63,7 @@
       "dbeaver-community"
       "discord"
       "feishu"
-      "fl-clash"
+      "goooler/repo/fl-clash"
       "ghostty"
       "keka"
       "logitech-g-hub"

modules/shared/nix.nix

@@ -1,17 +1,15 @@
-{ lib, ... }:
+{ lib, pkgs, ... }:
 
 {
-  nix.settings = {
+  # Determinate Nix manages the daemon on macOS
+  nix.enable = !pkgs.stdenv.isDarwin;
+
+  nix.settings = lib.mkIf (!pkgs.stdenv.isDarwin) {
     experimental-features = [
       "nix-command"
       "flakes"
     ];
     warn-dirty = false;
-    # 国内镜像（按需取消注释）
-    # substituters = [
-    #   "https://mirrors.tuna.tsinghua.edu.cn/nix-channels/store"
-    #   "https://cache.nixos.org"
-    # ];
   };
 
   nixpkgs = {