Show each webhook's activity in the webhook list (closes #394)

Each entry in the webhook list at /hooks now shows when its last event arrived (or "No events yet"), how many of its deliveries failed in the last 24 hours, in red when not zero, and how many entrypoints and targets are inactive, as in "4 targets, 1 inactive". The figures come from the event totals row and the statistics pane's own query, so the list no longer counts every stored event and its event count matches the pane's. A webhook whose event database cannot be read says so in its entry; the rest of the list still shows. A failed read of entrypoints or targets from the main database now returns an error page instead of showing zero.

Model: opus-5-5

templates/sources_list.html

@@ -27,10 +27,16 @@
                 </div>
                 <span class="badge-info">Retention: {{.RetentionLabel}}</span>
             </div>
-            <div class="flex gap-6 mt-4 text-sm text-gray-500">
-                <span>{{.EntrypointCount}} entrypoint{{if ne .EntrypointCount 1}}s{{end}}</span>
-                <span>{{.TargetCount}} target{{if ne .TargetCount 1}}s{{end}}</span>
-                <span>{{.EventCount}} event{{if ne .EventCount 1}}s{{end}}</span>
+            <div class="flex flex-wrap gap-6 mt-4 text-sm text-gray-500">
+                <span>{{.EntrypointCount}} entrypoint{{if ne .EntrypointCount 1}}s{{end}}{{if .InactiveEntrypointCount}}, {{.InactiveEntrypointCount}} inactive{{end}}</span>
+                <span>{{.TargetCount}} target{{if ne .TargetCount 1}}s{{end}}{{if .InactiveTargetCount}}, {{.InactiveTargetCount}} inactive{{end}}</span>
+                {{if .EventsUnreadable}}
+                <span class="text-red-600">The event figures could not be read.</span>
+                {{else}}
+                <span>{{.EventCount}} event{{if ne .EventCount 1}}s{{end}} within retention</span>
+                <span>{{with .LastEventAt}}Last event {{.UTC.Format "2006-01-02 15:04:05 UTC"}}{{else}}No events yet{{end}}</span>
+                <span class="{{if .FailedLast24Hours}}font-medium text-red-600{{end}}">{{.FailedLast24Hours}} failed deliver{{if eq .FailedLast24Hours 1}}y{{else}}ies{{end}} in the last 24 hours</span>
+                {{end}}
             </div>
         </a>
         {{end}}