feat(timeline): record a change by hand from the Timeline, a host's page or MCP log_change (#6350)

A change Steward can't see happen (a config edited, a disk swapped) is
recorded by whoever made it: what was done, its area, when (in the reader's
own zone), the hosts, what it was done to and a detail. Its author or an
admin edits or deletes it; recording, editing and deleting are audited and
those audit rows stay off the timeline. log_change records one as
"<user> via MCP", editable by the token's user.

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

docs/core/mcp.md

@@ -78,7 +78,7 @@ Each role includes the tools of the roles above it in this list.
 | 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) |
 | 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, changes to Steward's settings; by host, area or kind, and kept after the records it came from age out) |
+| 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) |
 | Docker plugin | `list_containers`, `get_container`, `list_swarm_services`, `search_container_logs`, `get_docker_disk_usage` |
 | Host agent (built in, always on) | `list_agents`, `list_maintenance_plans` (each plan's group, weekly slot, next run and latest run: how far it got, who it skipped and why), `get_maintenance_job` (a host's update jobs or one job: state, packages updated, whether it rebooted, why it failed), `get_host_senders` (who sent or received a host's network traffic over a window: its containers and NFS mounts ranked at the host's peak, and what none of them accounts for) |
 | Traefik plugin | `list_routers` (each router graded as the Traefik page grades it, with the status codes behind a problem, what they mean and the swarm service behind it), `get_router` (one router's history, codes, normal and anomalies), `list_certificates` (served certificates, days left, the routers they cover), `get_traffic` (the access log's clients, countries and routers, and Traefik's own figures) |
@@ -95,6 +95,7 @@ Each role includes the tools of the roles above it in this list.
 | Monitors | `create_monitor`, `update_monitor`, `set_monitor_enabled` |
 | Alerts | `create_alert_rule`, `update_alert_rule`, `acknowledge_alert`, `send_test_alert`, `create_maintenance_window`, `end_maintenance_window` |
 | Metric anomalies | `review_anomaly` (mark one or several normal, so their hours are learned, or real, with a note saying why) |
+| Timeline | `log_change` (record a change Steward can't see happen — a config edited by hand, a disk swapped — on the hosts it was done on, under an area; shown as by "<you> via MCP") |
 
 ### Admin: destructive and remediation