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/designers/language-modifiers/language-modifier-default.md

@@ -0,0 +1,45 @@
+# default
+
+This is used to set a default value for a variable. If the variable is
+unset or an empty string, the given default value is printed instead.
+Default takes the one argument.
+
+## Basic usage
+```smarty
+{$myVar|default:"(none)"}
+```
+
+## Parameters
+
+| Parameter | Type   | Required | Default | Description                                                   |
+|-----------|--------|----------|---------|---------------------------------------------------------------|
+| 1         | string | No       | *empty* | This is the default value to output if the variable is empty. |
+
+## Examples
+
+```php
+<?php
+
+    $smarty->assign('articleTitle', 'Dealers Will Hear Car Talk at Noon.');
+    $smarty->assign('email', '');
+
+```
+
+Where template is:
+
+```smarty
+{$articleTitle|default:'no title'}
+{$myTitle|default:'no title'}
+{$email|default:'No email address available'}
+```  
+
+Will output:
+
+```
+Dealers Will Hear Car Talk at Noon.
+no title
+No email address available
+```
+
+See also the [default variable handling](../../appendixes/tips.md#default-variable-handling) and
+the [blank variable handling](../../appendixes/tips.md#blank-variable-handling) pages.