chore: initialize orderPRO with docs, i18n and scss asset pipeline

src/Core/Support/Flash.php

@@ -0,0 +1,38 @@
+<?php
+declare(strict_types=1);
+
+namespace App\Core\Support;
+
+final class Flash
+{
+    private const FLASH_KEY = '_flash';
+
+    public static function set(string $key, mixed $value): void
+    {
+        if (!isset($_SESSION[self::FLASH_KEY]) || !is_array($_SESSION[self::FLASH_KEY])) {
+            $_SESSION[self::FLASH_KEY] = [];
+        }
+
+        $_SESSION[self::FLASH_KEY][$key] = $value;
+    }
+
+    public static function get(string $key, mixed $default = null): mixed
+    {
+        if (
+            !isset($_SESSION[self::FLASH_KEY]) ||
+            !is_array($_SESSION[self::FLASH_KEY]) ||
+            !array_key_exists($key, $_SESSION[self::FLASH_KEY])
+        ) {
+            return $default;
+        }
+
+        $value = $_SESSION[self::FLASH_KEY][$key];
+        unset($_SESSION[self::FLASH_KEY][$key]);
+
+        if (empty($_SESSION[self::FLASH_KEY])) {
+            unset($_SESSION[self::FLASH_KEY]);
+        }
+
+        return $value;
+    }
+}