/// Opaque box class retained by Rust via `Unmanaged<{{ box_name }}>.passRetained`.
/// Each `alef_*` method corresponds to an `extern "Swift"` declaration in the
/// Rust bridge crate; swift-bridge generates @_cdecl shims that call these.
/// Delegates to a `{{ delegate_protocol_name }}` (implemented in the main module).
public final class {{ box_name }} {
    private let delegate: any {{ delegate_protocol_name }}
    public init(_ delegate: any {{ delegate_protocol_name }}) { self.delegate = delegate }
