The OS/Kernel/Uptime/CPU/Swap strip was the only section on the System
page rendered without a .sys-section-head, so it had no title and butted
directly against the charts above it (no top spacing). Add a "Host" head
— matching the Docker / Per-app pattern — which supplies both the label
and the section's 26px top margin. "Host" rather than "System" since the
page H1 is already "System".
Signed-off-by: librelad <librelad@digitalangels.vip>
9c6cef5a05