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-compile-check.md

@@ -0,0 +1,30 @@
+\$compile\_check {#variable.compile.check}
+================
+
+Upon each invocation of the PHP application, Smarty tests to see if the
+current template has changed (different timestamp) since the last time
+it was compiled. If it has changed, it recompiles that template. If the
+template has yet not been compiled at all, it will compile regardless of
+this setting. By default this variable is set to TRUE.
+
+Once an application is put into production (ie the templates won\'t be
+changing), the compile check step is no longer needed. Be sure to set
+`$compile_check` to FALSE for maximum performance. Note that if you
+change this to FALSE and a template file is changed, you will \*not\*
+see the change since the template will not get recompiled.
+
+Note that up to Smarty 4.x, Smarty will check for the existence of 
+the source template even if `$compile_check` is disabled.
+
+If [`$caching`](#variable.caching) is enabled and `$compile_check` is
+enabled, then the cache files will get regenerated if an involved
+template file or config file was updated.
+
+As of Smarty 3.1 `$compile_check` can be set to the value
+`Smarty::COMPILECHECK_CACHEMISS`. This enables Smarty to revalidate the
+compiled template, once a cache file is regenerated. So if there was a
+cached template, but it\'s expired, Smarty will run a single
+compile\_check before regenerating the cache.
+
+See [`$force_compile`](#variable.force.compile) and
+[`clearCompiledTemplate()`](#api.clear.compiled.tpl).