Selected items on other pages are hit by batch actions, including permanent deletes #3954

Initial Checklist

• I understand this is a bug report and questions should be posted in the Community Discussions
• I searched issues and couldn’t find anything (or linked relevant results below)

Bug Description

A selection survives page changes and sorting, and batch actions also hit the selected items you can't see anymore. I think this is critical: tick an item on page 3, forget about it, go back to page 1, tick an item there and delete it, and the item on page 3 gets deleted as well. In files it at least lands in the trash, but in the admin settings (users, groups, spaces) and in the trash bin the delete is permanent.

Confirmed on main (f530b93) with 20 items per page:

In the files views the header checkbox even shows "all selected" on page 2 with no ticked row, because it only compares counts (useResourceViewSelection.ts:36-42). The selection is stored globally and nothing removes items when they leave the view (useResourcesViewDefaults.ts, admin UsersList.vue/GroupsList.vue/SpacesList.vue), and the batch actions, the "N selected" bar and drag and drop use the whole stored selection.

Reproduction Steps

1. Admin settings > Users, 20 per page, at least 21 users.
2. Click the "select all" checkbox on page 1.
3. Go to page 2 and tick one user.
4. Click "Delete" in the batch bar.

Expected Outcome

Only what's visible is selected: items that leave the view (page, sort, filter, tab) leave the selection, and "select all" is based on the visible rows.

Actual Outcome

The dialog asks to delete 21 users and deletes the 20 users from page 1 too.