feat(alerts): alert history page — transitions, deliveries, mutes and actions (#5066)

#5066 "Alert history page". /alerts/history lists every alert transition
in a range (1h–30d, the shared range picker), newest first, all rules or
one (?rule=). Each row: from → to, the value against the rule's condition
("no data" for a silent one), email and webhook sent or failed with the
error, "muted · <window>" (and "notified when the window ended") taken out
of the event note, other notes, and a link to the Ansible run an action
started. Range and rule changes swap only the rows (HTMX). Viewer role.

The Alerts page links each rule's history and the whole history. The query
moves to alert_svc.history, which MCP get_alert_history now uses too.

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

steward/mcp/tools/alerts.py

@@ -7,7 +7,7 @@ from sqlalchemy import select
 
 from steward.alerts import service as alert_svc
 from steward.mcp._context import current_caller
-from steward.models.alerts import AlertEvent, AlertOperator, AlertRule, AlertState, MaintenanceWindow
+from steward.models.alerts import AlertOperator, AlertRule, AlertState, MaintenanceWindow
 from steward.models.users import User, UserRole
 
 from ._audit import audit_mcp
@@ -95,16 +95,8 @@ async def get_alert_history(rule: str = "", range: str = "7d", limit: int = 50)
     limit = clamp_limit(limit, 50, 500)
     async with db_session() as db:
         rules = await alert_svc.list_rules(db)
-        stmt = (select(AlertEvent, AlertRule)
-                .join(AlertRule, AlertEvent.rule_id == AlertRule.id)
-                .where(AlertEvent.transitioned_at >= since)
-                .order_by(AlertEvent.transitioned_at.desc())
-                .limit(limit + 1))
-        chosen = None
-        if rule:
-            chosen = pick(rule, rules, kind="alert rule", list_tool="list_alert_rules")
-            stmt = stmt.where(AlertEvent.rule_id == chosen.id)
-        rows = (await db.execute(stmt)).all()
+        chosen = pick(rule, rules, kind="alert rule", list_tool="list_alert_rules") if rule else None
+        rows = await alert_svc.history(db, since, chosen.id if chosen else None, limit)
     events = [
         {
             "rule_id": r.id,