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/api-functions/api-template-exists.md

@@ -0,0 +1,59 @@
+templateExists()
+
+checks whether the specified template exists
+
+Description
+===========
+
+bool
+
+templateExists
+
+string
+
+template
+
+It can accept either a path to the template on the filesystem or a
+resource string specifying the template.
+
+This example uses `$_GET['page']` to
+[`{include}`](#language.function.include) a content template. If the
+template does not exist then an error page is displayed instead. First
+the `page_container.tpl`
+
+
+    <html>
+    <head><title>{$title}</title></head>
+    <body>
+    {include file='page_top.tpl'}
+
+    {* include middle content page *}
+    {include file=$content_template}
+
+    {include file='page_footer.tpl'}
+    </body>
+
+      
+
+And the php script
+
+
+    <?php
+
+    // set the filename eg index.inc.tpl
+    $mid_template = $_GET['page'].'.inc.tpl';
+
+    if( !$smarty->templateExists($mid_template) ){
+        $mid_template = 'page_not_found.tpl';
+    }
+    $smarty->assign('content_template', $mid_template);
+
+    $smarty->display('page_container.tpl');
+
+    ?>
+
+      
+
+See also [`display()`](#api.display), [`fetch()`](#api.fetch),
+[`{include}`](#language.function.include) and
+[`{insert}`](#language.function.insert)