feat(goose-cli): add package and update configurations

- Added `goose-cli` package definition and metadata in `unstable` overlay.
- Updated `default.nix` under `aarch64-darwin` to include `goose-cli` in system packages.
- Removed commented out packages and cleaned up unused lines for better clarity and maintainability.

overlays/unstable/default.nix

@@ -5,7 +5,7 @@ final: prev: {
     ollama
     open-webui
     claude-code
-    goose-cli
     aider-chat
     ;
+  goose-cli = channels.unstable.callPackage ./goose.nix { };
 }