feat(tickets): open, comment and resolve tickets from the UI and MCP; known issues on alerts and anomalies (#6351, #6352)

A ticket records a known problem: title, area, hosts, subject, description,
links to alert rules and anomalies, and a log of comments, edits, resolving
and reopening. Opening, resolving (with the resolution as the note) and
reopening go on the timeline; every step is audited, and the audit rows stay
off the timeline.

An alert or anomaly an open ticket covers (by link, by subject, or a
host-wide ticket on the host itself) shows a Known issue badge, and offers
"Open a ticket" prefilled from its rule or anomaly when none does. Hosts,
monitors and containers get a Known issues card.

MCP: list_tickets, get_ticket (viewer); open_ticket, update_ticket,
comment_ticket, resolve_ticket, reopen_ticket (operator). list_alerts and
list_anomalies carry known_issue; get_overview, get_host, get_monitor and
get_container carry open_tickets. Also update_change and delete_change for
changes recorded by hand (author or admin).

Tickets are left out of backups, like the timeline (2026-10-15 ruling).

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

steward/templates/hosts/detail.html

@@ -202,6 +202,9 @@
   {% endif %}
 </div>{# Ansible card #}
 
+{# ── Known issues: this host's open tickets ──────────────────────────────── #}
+<div hx-get="/tickets/card?host={{ host.name|urlencode }}&amp;back={{ ('/hosts/' ~ host.id)|urlencode }}" hx-trigger="load" hx-swap="outerHTML"></div>
+
 {# ── History: what happened to this host lately (timeline) ─────────────────── #}
 <div hx-get="/timeline/host/{{ host.id }}" hx-trigger="load" hx-swap="innerHTML">
   <div class="card"><span style="color:var(--text-muted);font-size:0.85rem;">Loading history…</span></div>