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-string-format.md

@@ -0,0 +1,43 @@
+# string_format
+
+This is a way to format strings, such as decimal numbers and such. Use
+the syntax for [`sprintf()`](https://www.php.net/sprintf) for the
+formatting.
+
+## Basic usage
+```smarty
+{$myVar|string_format:"%d"}
+```
+
+## Parameters
+
+| Parameter Position | Type   | Required | Description                           |
+|--------------------|--------|----------|---------------------------------------|
+| 1                  | string | Yes      | This is what format to use. (sprintf) |
+
+## Examples
+
+```php
+<?php
+
+$smarty->assign('number', 23.5787446);
+
+```
+
+Where template is:
+
+```smarty
+{$number}
+{$number|string_format:"%.2f"}
+{$number|string_format:"%d"}
+```
+
+Will output:
+
+```
+23.5787446
+23.58
+23
+```
+
+See also [`date_format`](language-modifier-date-format.md).