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/app.py

@@ -234,6 +234,7 @@ def create_app(
     from .ai_access.routes import ai_access_bp
     from .account.routes import account_bp
     from .timeline.routes import timeline_bp
+    from .tickets.routes import tickets_bp
 
     app.register_blueprint(auth_bp)
     app.register_blueprint(dashboard_bp)
@@ -249,6 +250,7 @@ def create_app(
     app.register_blueprint(ai_access_bp)
     app.register_blueprint(account_bp)
     app.register_blueprint(timeline_bp)
+    app.register_blueprint(tickets_bp)
 
     # Register the unified Monitor status source for the Status page. Plugins
     # may register additional sources from setup(). Idempotent.