feat(hosts): the hottest sensor is named with its chip, and the host-reading cutoffs are read and set over MCP (#6806)

Agent 1.27.0 sends each temperature sensor's hwmon chip. Steward keeps the
chip per host and label beside the reading, so a sensor's metric key stays
its label, and the strip and the heat alert name it as "NVMe · Sensor 2"
rather than a bare "Sensor 2".

get_thresholds (viewer) and set_thresholds (admin, audited) read and change
the warn/crit cutoffs CPU, memory, disk, load and temperature are graded by,
as Settings → Thresholds does.

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

steward/mcp/tools/__init__.py

@@ -13,10 +13,10 @@ each argument's empty value means, and what comes back.
 from __future__ import annotations
 
 from . import (alerts, anomalies, audit, automation, backups, hosts, metrics, monitors, overview, session,
-               tickets, timeline)
+               thresholds, tickets, timeline)
 
-_MODULES = (session, overview, hosts, monitors, alerts, anomalies, metrics, audit, timeline, tickets,
-            automation, backups)
+_MODULES = (session, overview, hosts, monitors, alerts, anomalies, thresholds, metrics, audit, timeline,
+            tickets, automation, backups)
 
 
 def register_all(register_tool) -> None: