feat(host_agent): a disk out of inodes reads as full (#5745)

VDNT-Util01's / ran out of inodes (956 free of 60.8M) with 274G of space
left; every file create failed and Steward's page read healthy at 66%.

- Agent 1.13.0 reports each mount's inodes (statvfs; a filesystem reporting
  none, like btrfs, is left without).
- Ingest records inodes_used_pct per mount, and disk_used_pct_worst is the
  fullest mount by space or inodes, so existing disk-full rules and the
  overview see it.
- The host's health strip, the Hosts widget and the host glance grade / by
  whichever is fuller and name inodes when they are ("Disk / 66% · inodes
  100%", "Inodes on / ... past its critical threshold").

Hosts pick up the inode figures once their agent is updated to 1.13.0.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

plugins/host_agent/templates/_host_vitals.html

@@ -25,7 +25,9 @@
   <div class="stat-strip host-health-tiles" style="margin-bottom:0;">
     {{ stat_tile("CPU", pct(cpu), state=(grades.cpu or [status_class(cpu, 'cpu')])[0], hint=sparks.cpu|safe) }}
     {{ stat_tile("Memory", pct(mem), state=(grades.mem or [status_class(mem, 'mem')])[0], hint=sparks.mem|safe) }}
-    {{ stat_tile("Disk /", pct(disk_root), state=(grades.disk or [status_class(disk_root, 'disk')])[0], hint=sparks.disk|safe) }}
+    {%- set inodes_worse = inodes_root is defined and inodes_root is not none and (disk_root is none or inodes_root > disk_root) %}
+    {{ stat_tile("Disk /", pct(disk_root) ~ (" · inodes " ~ pct(inodes_root) if inodes_worse else ""),
+                 state=(grades.disk or [status_class(disk_root, 'disk')])[0], hint=sparks.disk|safe) }}
     {{ stat_tile("Load per core", pct(load_per_core), state=(grades.load or [status_class(load_per_core, 'load')])[0], hint=sparks.load|safe) }}
   </div>
   {% if usual and not stale %}