Constructor parameter attribute — injects the Principal stamped by
AuthenticationMiddleware onto the request. Mirrors #[FromActor] /
#[FromService] / #[FromBody] in nexus-http.
Recognized by patched nexus-http/HandlerResolver and
nexus-http-ws/HandlerInstantiator via class-string lookup, so this
package doesn't need to be imported by those.
public function __construct(
#[FromPrincipal] private readonly Principal $principal,
) }