fix(listener): notify callback based on signedNodeId/signedHash

[henmohr]

Problem

The webhook/callback configured via the callback field of request-signature was never fired after the document was signed.

Root cause

SignedCallbackListener::handle() checked for a signed key in the entity's updated fields:

if (isset($updatedFields['signed']) && $updatedFields['signed'] === true) {
    $this->signFileService->notifyCallback($event->getSignedFile());
}

However, the File entity does not have a signed field. The signature is tracked by signedNodeId and signedHash, which are set in SignFileService::updateLibreSignFile() (via setSignedNodeId/setSignedHash). As a result the condition was always false and the callback was never notified.

Fix

Check signedNodeId/ signedHash instead:

if (!empty($updatedFields['signedNodeId']) || !empty($updatedFields['signedHash'])) {
    $this->signFileService->notifyCallback($event->getSignedFile());
}

Testing

Verified against Nextcloud 35 + LibreSign stable35: after signing, the callback URL now receives the multipart POST (uuid, status, file) automatically. Previously it required a manual invocation of the callback endpoint.