feat(ui): alerts, monitors, hosts, schedules and maintenance lists put problems first, with since-times (#5210)

#5210 "Problems first, with since-time, across every list" (milestone 477),
first batch.

- Alerts: the Active list reads firing, no data, acknowledged, pending, the
  longest-running first, and re-polls itself. An acknowledged alert says how
  long it has been breaching (from the alert's events; acknowledging moves
  last_transition_at) and, apart from that, who acknowledged it and when.
  Rules show what each is doing now; disabled rules sort last. The current
  value reads the latest-value table (#5208) instead of plugin_metrics.
- Monitors: a down monitor says "Down 12m · connection refused" in the list.
- Hosts: sorted down, agent gone quiet, pending, healthy. The agent column
  shows "—" for a missing reading (was 0%) and a Stale badge with its age.
  agent_metrics_by_host is gone; the list reads agent_overview_by_host.
- Schedules: failing first (failed or interrupted run, or a firing that could
  not start one), then running, then the rest, paused last; status badge
  from the shared states.
- Maintenance windows: active (ending soonest), then upcoming (starting
  soonest), with expired folded away; each says when it ends/starts/ended.

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

steward/ansible/routes.py

@@ -443,6 +443,7 @@ async def schedules():
         })
         if editing_id and s.id == editing_id:
             editing = s
+    rows.sort(key=_schedule_order)
 
     # Default the source dropdown to the first source (or the edited schedule's
     # source), and pre-render that source's playbooks so the playbook dropdown
@@ -472,6 +473,23 @@ async def schedules():
     )
 
 
+def _schedule_order(row: dict) -> tuple:
+    """Schedules list order: failing first (its last run failed or was cut
+    short, or its last firing could not start one), then running, then the
+    rest, paused last; by name within each."""
+    s, run = row["s"], row["last_run"]
+    status = run.status.value if run else None
+    if not s.enabled:
+        rank = 3
+    elif status in ("failed", "interrupted") or (s.last_error and run is None):
+        rank = 0
+    elif status in ("queued", "running"):
+        rank = 1
+    else:
+        rank = 2
+    return rank, s.name.lower()
+
+
 def _schedule_form_fields(form) -> tuple[dict | None, str | None]:
     """Validate + extract schedule fields from a form. Returns (fields, error)."""
     name = (form.get("name", "") or "").strip()