Playground plugin: Doesn't work in Playground because of ZipStream dependency

[adamziel]

Here's a few errors I stumbled upon when trying to run the Playground plugin inside Playground:

PHP 8.0:

[16-Apr-2024 21:52:18 UTC] PHP Parse error:  syntax error, unexpected identifier "Closure", expecting variable in /wordpress/wp-content/plugins/playground/vendor/maennchen/zipstream-php/src/ZipStream.php on line 111

PHP 8.3:

PHP Fatal error:  Uncaught ValueError: 64-bit format codes are not available for 32-bit versions of PHP in /wordpress/wp-content/plugins/playground/vendor/maennchen/zipstream-php/src/PackField.php:55

We already have a stream zip decoder written in PHP. Let's also port the TypeScript encoder to PHP 7.0–compatible code and use that instead.