The list view of Current Slots gets a checkbox per unbooked slot, a
select-all header checkbox, and a Delete selected button submitting a
new bulk_delete form action. Each id is ownership-checked through the
same path as single delete; the repository's is_booked guard refuses
booked slots as a second layer. Row checkboxes attach to the bulk form
via the HTML form attribute because the table already contains the
per-row delete forms and forms cannot nest.
Closes#57
Co-Authored-By: Claude Fable 5 <[email protected]>
