fix(darwin): put aichat config in right place for darwin

nix/homes/rafiq/darwin.nix

@@ -0,0 +1,21 @@
+{ lib, ... }:
+let
+  inherit (lib.modules) mkIf;
+in
+{
+  flake.modules.homeManager.rafiq =
+    {
+      pkgs,
+      config,
+      hostName,
+      hostConfig,
+      ...
+    }:
+    mkIf (pkgs.system == "aarch64-darwin" || pkgs.system == "x86_64-darwin") {
+      home.file."Library/Application Support/aichat/config.yaml".text = ''
+        model: gemini:gemini-2.0-flash
+        clients:
+        - type: gemini
+      '';
+    };
+}