feat(utils): add Str class to utils

[wd006]

Overview

A class named Str has been added to the utilities.

Key Changes

• random: A function that returns a random string of a desired length has been added.

How to Test

1. Create a temporary file (e.g. test.php) in the root directory.
2. Paste the following code:

<?php

require_once __DIR__ . '/init.php'; 

$randomString = Str::random(10);

echo "Randomized: " . $randomString . "<br>";
echo "Length: " . strlen($randomString);

3. Run the script via browser or terminal.
4. Verify that the output string is 10 characters long.