Changed
- Viewer/dashboard: the section payload no longer carries
num_series.
Computing it counted every label set of every metric, which on a.rez
forced every table's reader to be built — for an indexed table, replaying
the identity index — the first time/api/v1/sectionswas asked, and
re-walked the labels on every ask after that, undoing the lazy open for
the first request a page makes. The rezolus viewer never rendered the
number; systemslab's metrics page showed it as "N series" and drops that
label in iopsystems/systemslab#6268.