ui: show metric name inline with hostname in alerts and notifications

Alerts page: move metric name into the header row alongside hostname.
Notifications: include metric name in title (hostname  metric) and
strip the metric prefix from the body so it contains only value/detail.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

hbd/server/templates/alerts.html

@@ -184,9 +184,9 @@
     }
 
     .alert-metric {
-      color: #666;
-      font-family: 'Courier New', monospace;
-      font-size: 0.9em;
+      color: #0066cc;
+      font-size: 0.85em;
+      font-weight: normal;
     }
 
     .alert-details {
@@ -438,8 +438,8 @@
               <div class="alert-header">
                 <span class="alert-level ${level}">${alert.level}</span>
                 <a class="alert-hostname" href="/plugins#${alert.hostname}">${alert.hostname}</a>
+                <span class="alert-metric">${alert.metric_path.includes('.') ? alert.metric_path.slice(alert.metric_path.indexOf('.') + 1) : alert.metric_path}</span>
               </div>
-              <div class="alert-metric">${alert.metric_path.includes('.') ? alert.metric_path.slice(alert.metric_path.indexOf('.') + 1) : alert.metric_path}</div>
               <div class="alert-details">
                 <span>${valueText}</span>
                 <span class="alert-duration">Active for ${duration}</span>