macOS laptops have no dedicated Forward Delete key. Fn+Backspace is the
only way to send \e[3~, and many macOS terminals (Terminal.app, some
iTerm2 profiles) deliver \x7f for that combo instead — so the keystroke
landed in the search box, not the delete handler, making session deletion
unreachable for those users.
Add a Backspace-on-empty-search handler alongside the existing Delete
check. With a typed query, Backspace stays bound to the search Input so
users can still edit their filter text. The existing confirmation dialog
guards against accidents.
Footer hint updated: [Del delete] -> [Del/⌫ delete].