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-cache-dir.md

@@ -0,0 +1,35 @@
+\$cache\_dir {#variable.cache.dir}
+============
+
+This is the name of the directory where template caches are stored. By
+default this is `./cache`, meaning that Smarty will look for the
+`cache/` directory in the same directory as the executing php script.
+**This directory must be writeable by the web server**, [see
+install](#installing.smarty.basic) for more info.
+
+You can also use your own [custom cache implementation](#caching.custom)
+to control cache files, which will ignore this setting. See also
+[`$use_sub_dirs`](#variable.use.sub.dirs).
+
+> **Note**
+>
+> This setting must be either a relative or absolute path. include\_path
+> is not used for writing files.
+
+> **Note**
+>
+> It is not recommended to put this directory under the web server
+> document root.
+
+> **Note**
+>
+> As of Smarty 3.1 the attribute \$cache\_dir is no longer accessible
+> directly. Use [`getCacheDir()`](#api.get.cache.dir) and
+> [`setCacheDir()`](#api.set.cache.dir) instead.
+
+See also [`getCacheDir()`](#api.get.cache.dir),
+[`setCacheDir()`](#api.set.cache.dir), [`$caching`](#variable.caching),
+[`$use_sub_dirs`](#variable.use.sub.dirs),
+[`$cache_lifetime`](#variable.cache.lifetime),
+[`$cache_modified_check`](#variable.cache.modified.check) and the
+[caching section](#caching).