chore(viewer): setup psalm and resolve issues

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

Author: susnux

apps/viewer/lib/AppInfo/Application.php

@@ -25,10 +25,12 @@ public function __construct() {
 		parent::__construct(self::APP_ID);
 	}
 
+	#[\Override]
 	public function register(IRegistrationContext $context): void {
 		$context->registerEventListener(LoadViewer::class, LoadViewerScript::class);
 	}
 
+	#[\Override]
 	public function boot(IBootContext $context): void {
 	}
 }

apps/viewer/lib/Listener/LoadViewerScript.php

@@ -33,6 +33,7 @@ public function __construct(
 		$this->previewManager = $previewManager;
 	}
 
+	#[\Override]
 	public function handle(Event $event): void {
 		if (!($event instanceof LoadViewer || $event instanceof LoadAdditionalScriptsEvent)) {
 			return;

psalm.xml

@@ -52,6 +52,7 @@
 		<directory name="apps/updatenotification"/>
 		<directory name="apps/user_ldap"/>
 		<directory name="apps/user_status"/>
+		<directory name="apps/viewer"/>
 		<directory name="apps/weather_status"/>
 		<directory name="apps/webhook_listeners"/>
 		<directory name="apps/workflowengine"/>