feat(dashboard): Monitors widget carries uptime; Uptime / SLA retired (#5250)

The Monitors widget opens with a verdict ("1 of 5 monitors down."), then one
row per monitor under a single header: latency and uptime over 24h, 7d and
30d, down monitors first with why and since when, the name linking to the
monitor. Counts follow the type filter. Problems always show; the limit
trims only the healthy rest ("+N more up").

Uptime / SLA (uptime_summary) repeated those numbers per host; migration
0033 moves dashboards onto Monitors. Shared widget styles (.w-verdict,
.w-table, .w-sub, .w-more) carry the widget-shape ruling for the widgets
that follow.

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

steward/monitors/service.py

@@ -204,6 +204,7 @@ async def monitor_rows(db, range_key: str, thresholds: dict):
             "heartbeat": [{"state": "up" if r.is_up else "down",
                            "title": _heartbeat_title(m.type, r)} for r in rows],
             "uptime_pct": uptime_pct,
+            "uptime": uptime.get(m.id, {}),
             "tls_days": tls_days,
             "down_since": None,
             "down_reason": down_reason(latest) if latest is not None and not latest.is_up else None,