The idle-gate reads LastActivities, which only tracks per-peer data in userspace;
in kernel mode it is empty, so the gate treated every kernel peer as idle and
disabled data-path rotation entirely. Detect the bind via IsUserspaceBind and, in
kernel mode, report zero activity age (always 'active') so rotation runs on every
rekey. Lazy back-to-idle is already limited in kernel; the eBPF WG-activity
detection will later supply a real signal that excludes handshake/pqkem traffic.