When the daemon holds background work back for a busy host, a user
looking at a stale topology or an unfinished repair scan needs to see
why. Status had no host signal at all.
Carry the governor's host sample through the metrics snapshot and
StatusResponse: source (psi, loadavg), whether the host counts as busy,
the PSI cpu/io/memory "some avg10" values or the per-CPU load average,
and which deferrable work is currently held back. The proto transport
piggybacks the fields on request_counts like the other string status
fields; the native serializer appends them as optional tail fields.
`yams daemon status` (brief and detailed) shows a Host Load row, e.g.
"Busy cpu 72% · io 3% · mem 0% · deferring topology, repair", and
`yams status --json` gains a host_pressure object. Document the new
[tuning.resource] keys next to the other typed tuning sections.
Signed-off-by: trvon <me@trevon.dev>
1fa2e92510