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>

docs/core/mcp.md

@@ -76,6 +76,7 @@ Each role includes the tools of the roles above it in this list.
 | Monitors | `list_monitors`, `get_monitor` |
 | Alerts | `list_alerts`, `get_alert_history`, `list_alert_rules`, `get_alert_rule_options`, `list_maintenance_windows` |
 | Metric anomalies | `list_anomalies` (metrics that left their normal for the hour, to review first), `get_anomaly` (one anomaly with each occurrence against what is usual at that hour, the metric around it, what else happened on its host — alerts, Ansible runs, container deaths and starts, maintenance, reboots, other anomalies — and how earlier ones on the same metric were judged), `get_metric_normal` (the learned normal slot by slot, and the level that would be flagged), `get_anomaly_settings` (the review window and each floor) |
+| Thresholds | `get_thresholds` (the warn and crit cutoffs CPU, memory, disk, load and temperature are graded by on the pages) |
 | Automation | `list_playbooks`, `get_playbook`, `list_inventory`, `list_ansible_runs`, `get_ansible_run`, `wait_for_run`, `list_schedules` |
 | Audit | `list_audit_events` |
 | Timeline | `get_timeline` (everything that happened, newest first, in one list: alerts firing and clearing, playbook runs and what they changed, maintenance, reboots, deploys and crash-loops, reviewed anomalies, changes recorded by hand, changes to Steward's settings; by host, area or kind, and kept after the records it came from age out) |
@@ -102,7 +103,8 @@ Each role includes the tools of the roles above it in this list.
 ### Admin: destructive and remediation
 
 `set_anomaly_settings` (the anomaly review window and each normal's floor, as
-Settings → Thresholds sets them), `set_alert_action` (the playbook a rule runs when it fires), `delete_monitor`,
+Settings → Thresholds sets them), `set_thresholds` (the warn and crit cutoffs host
+readings are graded by, as the same page sets them), `set_alert_action` (the playbook a rule runs when it fires), `delete_monitor`,
 `delete_alert_rule`, `prune_docker`, `run_maintenance` (update a host now, rebooting
 only if the update needs it, as the host page's Update now does).