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-escape-html.md

@@ -0,0 +1,21 @@
+\$escape\_html {#variable.escape.html}
+==============
+
+Setting `$escape_html` to TRUE will escape all template variable output
+by wrapping it in
+`htmlspecialchars({$output}, ENT_QUOTES, $char_set);`,
+which is the same as `{$variable|escape:"html"}`.
+
+Template designers can choose to selectively disable this feature by
+adding the `nofilter` flag: `{$variable nofilter}`.
+
+Modifiers and Filters are run in the following order: modifier,
+default\_modifier, \$escape\_html, registered variable filters,
+autoloaded variable filters, template instance\'s variable filters.
+Everything except the individual modifier can be disabled with the
+`nofilter` flag.
+
+> **Note**
+>
+> This is a compile time option. If you change the setting you must make
+> sure that the templates get recompiled.