feat: add reason of signature

lib/Handler/SignEngine/Pkcs12Handler.php

@@ -418,6 +418,7 @@ public function sign(): File {
 			->setPassword($this->getPassword())
 			->setSignatureParams($this->getSignatureParams())
 			->setVisibleElements($this->getVisibleElements())
+			->setReason($this->getReason())
 			->getSignedContent();
 		$this->getInputFile()->putContent($signedContent);
 		return $this->getInputFile();

lib/Handler/SignEngine/SignEngineHandler.php

@@ -16,6 +16,7 @@ abstract class SignEngineHandler implements ISignEngineHandler {
 	private File $inputFile;
 	protected string $certificate;
 	private string $password = '';
+	private string $reason = '';
 	/** @var VisibleElementAssoc[] */
 	private array $visibleElements = [];
 	private array $signatureParams = [];
@@ -59,6 +60,15 @@ public function getPassword(): string {
 		return $this->password;
 	}
 
+	public function setReason(string $reason): self {
+		$this->reason = $reason;
+		return $this;
+	}
+
+	public function getReason(): string {
+		return $this->reason;
+	}
+
 	/**
 	 * @param VisibleElementAssoc[] $visibleElements
 	 *

lib/Service/SignFileService.php

@@ -300,6 +300,9 @@ public function sign(): File {
 					->setVisibleElements($this->elements)
 					->setPassword($this->password)
 					->setSignatureParams($signatureParams)
+					->setReason($this->l10n->t('Signed by %s with LibreSign.coop', [
+						$this->signRequest->getDisplayName() . ' <' . $this->userUniqueIdentifier . '>'
+					]))
 					->sign();
 				break;
 			default: