v2.8.1

Ship SMART and IPMI alert rules with the Prometheus package

The smartctl/ipmi exporters and dashboards existed, but nothing alerted
when a drive or BMC sensor actually went bad. Nine disk rules (SMART
overall-health, NVMe critical-warning/spare/wear/media-errors, ATA
reallocated+pending sectors, SAS grown defects, uncorrected errors,
temperature) and three BMC rules (sensor critical/warning, collector
down). Metric names are taken from the queries the shipped dashboards
already use.

Like the Alertmanager-health rules, these live in the base rules.d and
are inert until matching series exist, so no per-exporter wiring is
needed. The *Increasing rules use delta() over 6h so drives with stable
historic error counts don't page forever.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>