Dev-Umgebung: Kompatibilität für PHP 8.3 + Smarty 4.5.6

- Smarty 4.1.1 → 4.5.6 (behebt dynamic property deprecations)
- Core-Klassen: #[\AllowDynamicProperties] für Admin_role, base, Config,
  Customer, Customer_group, CustomerGroups, Item, Structure, website
- website.class.php: counts[parent_id] initialisieren vor ++ (PHP 8.1)
- layout.class.php: HTTP_ACCEPT_LANGUAGE mit isset-Guard
- website_init.php: session_status()-Check vor session_start
- .htaccess: HTTPS-Redirect via X-Forwarded-Proto (statt SERVER_PORT)
- themes/easyshop_advanced/media/: Parent-Theme-Assets nachgezogen
- .gitignore: smarty.4.1.1.bak ausschließen

libs/smarty/docs/programmers/smarty-constants.md

@@ -0,0 +1,26 @@
+Constants {#smarty.constants}
+=========
+
+SMARTY\_DIR {#constant.smarty.dir}
+===========
+
+This is the **full system path** to the location of the Smarty class
+files. If this is not defined in your script, then Smarty will attempt
+to determine the appropriate value automatically. If defined, the path
+**must end with a trailing slash/**.
+
+
+    <?php
+    // set path to Smarty directory *nix style
+    define('SMARTY_DIR', '/usr/local/lib/php/Smarty-v.e.r/libs/');
+
+    // path to Smarty windows style
+    define('SMARTY_DIR', 'c:/webroot/libs/Smarty-v.e.r/libs/');
+
+    // include the smarty class, note 'S' is upper case
+    require_once(SMARTY_DIR . 'Smarty.class.php');
+    ?>
+
+         
+
+See also [`$smarty.const`](../designers/language-variables/language-variables-smarty.md).