refactor: code quality via Rector, strict types where safe

rector.php gets the codeQuality set: declare(strict_types=1) in the 85
files where Rector finds no call relying on scalar type juggling (mostly
TCA and configuration, models, the content feed API and the import
command), "or die" as "|| die", instanceof instead of null checks for
object types, early returns and self:: in final classes.

Hotel::setRooms() goes instead of getting the property Rector wanted to
declare: nothing calls it, and there is no rooms column any more.

Checked locally: cache warmup, the ep:* commands load, frontend crawl
(~1,900 URLs) and the backchannel APIs render the same as before.

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

packages/ep_theme/Classes/Middleware/CdnImageMiddleware.php

@@ -47,7 +47,7 @@ final readonly class CdnImageMiddleware implements MiddlewareInterface
         $cdnBaseUrl = rtrim((string)($this->extensionConfiguration->get('ep_theme', 'cdnBaseUrl') ?? ''), '/');
         $contentType = $response->getHeaderLine('Content-Type');
         if ($cdnBaseUrl === ''
-            || !(str_starts_with($contentType, 'text/html') || str_starts_with($contentType, 'application/json'))
+            || !str_starts_with($contentType, 'text/html') && !str_starts_with($contentType, 'application/json')
         ) {
             return $response;
         }