fix(norms): templates grade by the cutoffs when handed no grade; the parts test reads inside transactions (#5742)

CI 9128: the host vitals and monitor templates required the new grades, so
callers (and tests) that render them without one failed; they now fall back
to status_class. The new integration test read outside begin(), which
autobegan the session.

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

steward/templates/monitors/rows.html

@@ -51,7 +51,7 @@
     {% if d.state in ('down', 'paused', 'pending') %}{{ status_badge(d.state) }}
     {% elif latest.response_ms is not none %}
       {% if d.spark %}<span class="mon-spark" title="Response time over the last 30 checks">{{ d.spark|safe }}</span>{% endif %}
-      <span class="tone-{{ d.latency }}"{% if d.latency_usual %} title="{{ d.latency_usual|capitalize }}"{% endif %}>{{ "%.0f"|format(latest.response_ms) }} ms</span>
+      <span class="tone-{{ d.latency or status_class(latest.response_ms, 'latency') }}"{% if d.latency_usual %} title="{{ d.latency_usual|capitalize }}"{% endif %}>{{ "%.0f"|format(latest.response_ms) }} ms</span>
     {% elif m.type == 'dns' and latest.resolved_ip %}<span class="tone-ok">{{ latest.resolved_ip }}</span>
     {% else %}{{ status_badge('up') }}{% endif %}
   </div>

steward/templates/monitors/widget.html

@@ -26,10 +26,11 @@
       {{- status_dot(d.state) -}}
       {% if session.user_id %}<a href="/monitors/{{ m.id }}">{{ m.name }}</a>{% else %}{{ m.name }}{% endif %}
       {%- if d.state == 'down' %}<span class="w-sub tone-crit">went down {{ d.down_since|ago if d.down_since else '' }}{% if d.down_reason %} · {{ d.down_reason }}{% endif %}</span>
-      {%- elif d.state == 'degraded' %}<span class="w-sub tone-warn">{% if d.latency == 'crit' %}slow replies{% else %}checks failing now and then{% endif %}</span>
+      {%- elif d.state == 'degraded' %}<span class="w-sub tone-warn">{% if (d.latency or status_class(latest.response_ms, 'latency') if latest else none) == 'crit' %}slow replies{% else %}checks failing now and then{% endif %}</span>
       {%- elif d.state == 'pending' %}<span class="w-sub">not checked yet</span>{% endif %}
     </td>
-    <td class="{{ 'tone-' ~ d.latency if d.latency in ('warn', 'crit') }}"{% if d.latency_usual %} title="{{ d.latency_usual|capitalize }}"{% endif %}>
+    {% set lat = (d.latency or status_class(latest.response_ms, 'latency')) if latest and latest.is_up and latest.response_ms is not none else none %}
+    <td class="{{ 'tone-' ~ lat if lat in ('warn', 'crit') }}"{% if d.latency_usual %} title="{{ d.latency_usual|capitalize }}"{% endif %}>
       {%- if latest and latest.is_up and latest.response_ms is not none %}{{ "%.0f"|format(latest.response_ms) }} ms{% else %}—{% endif -%}
     </td>
     {% for k in ("24h", "7d", "30d") %}{% set u = d.uptime.get(k) %}