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>

steward/mcp/tools/overview.py

@@ -127,7 +127,7 @@ def alert_findings(active, silent: dict[str, list[str]] | None = None) -> list[d
 
 
 _AGENT_CHECKS = (("cpu_pct", "cpu", "CPU"), ("mem_used_pct", "mem", "memory"),
-                 ("disk_used_pct_worst", "disk", "fullest disk"))
+                 ("disk_used_pct_worst", "disk", "fullest disk (space or inodes)"))
 
 
 def agent_findings(hosts, agent: dict, thresholds: dict,