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-variables/variable-template-dir.md

@@ -0,0 +1,36 @@
+\$template\_dir {#variable.template.dir}
+===============
+
+This is the name of the default template directory. If you do not supply
+a resource type when including files, they will be found here. By
+default this is `./templates`, meaning that Smarty will look for the
+`templates/` directory in the same directory as the executing php
+script. \$template\_dir can also be an array of directory paths: Smarty
+will traverse the directories and stop on the first matching template
+found.
+
+> **Note**
+>
+> It is not recommended to put this directory under the web server
+> document root.
+
+> **Note**
+>
+> If the directories known to `$template_dir` are relative to
+> directories known to the
+> [include\_path](https://www.php.net/ini.core.php#ini.include-path) you
+> need to activate the [`$use_include_path`](#variable.use.include.path)
+> option.
+
+> **Note**
+>
+> As of Smarty 3.1 the attribute \$template\_dir is no longer accessible
+> directly. Use [`getTemplateDir()`](#api.get.template.dir),
+> [`setTemplateDir()`](#api.set.template.dir) and
+> [`addTemplateDir()`](#api.add.template.dir) instead.
+
+See also [`Template Resources`](#resources),
+[`$use_include_path`](#variable.use.include.path),
+[`getTemplateDir()`](#api.get.template.dir),
+[`setTemplateDir()`](#api.set.template.dir) and
+[`addTemplateDir()`](#api.add.template.dir).