refactor: PHP 8.5 language features via Rector

rector.php gets the PHP sets up to 8.5. Mostly constructor promotion with
readonly properties, typed class constants, ??=, arrow functions,
str_contains/str_starts_with, catch without unused variables, array_any
and #[\Override] on overridden properties; array_key_exists() keys are
cast to string (null keys are deprecated in PHP 8.5). Long promoted
constructor signatures are wrapped one parameter per line.

Checked locally: a crawl of ~1,900 frontend URLs over all sites and the
backchannel APIs (/api/hotel, /api/product, content feed manifest and
records of every type) render the same as before.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/ep_theme/Classes/Middleware/CdnImageMiddleware.php

@@ -32,11 +32,11 @@ use TYPO3\CMS\Core\Http\Stream;
  *
  * Registered after the page resolver, so the /api/* responses of ep_products never pass here.
  */
-final class CdnImageMiddleware implements MiddlewareInterface
+final readonly class CdnImageMiddleware implements MiddlewareInterface
 {
-    private const PATTERN = '/(["\'])\/?(fileadmin|uploads|typo3temp\/assets\/(?:_processed_|images))/';
+    private const string PATTERN = '/(["\'])\/?(fileadmin|uploads|typo3temp\/assets\/(?:_processed_|images))/';
 
-    public function __construct(private readonly ExtensionConfiguration $extensionConfiguration)
+    public function __construct(private ExtensionConfiguration $extensionConfiguration)
     {
     }