fix(sharing): set STATUS_ACCEPTED when creating USERGROUP subshare on move

When an ownCloud-migrated group share (which has no per-user USERGROUP
subshare) is renamed for the first time, DefaultShareProvider::move()
inserts a new USERGROUP row without setting `accepted`. The column
defaults to 0 (STATUS_PENDING), causing MountProvider to skip the share
on the next request — the file disappears for the recipient.

Native Nextcloud group shares are unaffected because the accept flow
always creates the USERGROUP subshare and immediately sets
`accepted = STATUS_ACCEPTED` before the user can rename.

Fixes: #59791

AI-Assisted-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Anna Larch <anna@nextcloud.com>

Author: miaulalala

lib/private/Share20/DefaultShareProvider.php

@@ -601,6 +601,7 @@ public function move(IShare $share, $recipient) {
 						'permissions' => $qb->createNamedParameter($share->getPermissions()),
 						'attributes' => $qb->createNamedParameter($shareAttributes),
 						'stime' => $qb->createNamedParameter($share->getShareTime()->getTimestamp()),
+						'accepted' => $qb->createNamedParameter(IShare::STATUS_ACCEPTED),
 					])->executeStatement();
 			} else {
 				// Already a usergroup share. Update it.