feat(widgets): Routers and Hosts problem rows say since when (#5810)

Routers: a router in trouble reads 'started 2h ago' or 'all of the last
24 h', from problem_since over the day's history, read for the troubled
routers only (a certificate's problem carries its own date). Hosts: a
down host reads 'a monitor is down for 3h'; host_glance keeps the
down_since host_status already had.

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

plugins/traefik/templates/traefik/widget.html

@@ -24,7 +24,8 @@
     <td class="w-name" title="{{ r.name }}">
       {{- status_dot(r.state) -}}
       {{ r.name.split('@')[0] }}
-      {%- if r.why and r.state != "ok" %}<span class="w-sub tone-{{ r.state }}">{{ r.why }}</span>{% endif %}
+      {%- if r.why and r.state != "ok" %}<span class="w-sub tone-{{ r.state }}">{{ r.why }}
+        {%- if r.since_before %}, all of the last 24 h{% elif r.since %}, started {{ r.since|ago }}{% endif %}</span>{% endif %}
     </td>
     <td>{% if m.request_rate is none %}—{% else %}{{ "%.2f"|format(m.request_rate) }}{% endif %}</td>
     <td class="w-wide-only">{% if m.response_bytes_rate is none %}—{% else %}{{ m.response_bytes_rate|rate }}{% endif %}</td>