feat(webhook): time-series histogram stats endpoint + frontend chart

ordinis-admin-ui/src/routes/webhooks.$id.tsx

@@ -37,6 +37,7 @@ import {
 import type { WebhookTestPingResult } from '@/api/client'
 import { SCOPE_DOT } from '@/lib/scope-style'
 import { WebhookStatsCards } from '@/components/webhooks/WebhookStatsCards'
+import { WebhookStatsHistogram } from '@/components/webhooks/WebhookStatsHistogram'
 
 export const Route = createFileRoute('/webhooks/$id')({
   component: WebhookDetailPage,
@@ -207,10 +208,13 @@ function WebhookDetailPage() {
       </Panel>
 
       {/* Stats cards — счётчики per status + success rate. Aggregate
-          из 4 параллельных queries с size=1 (cheap). Visual time-series
-          chart — deferred follow-up (требует /stats endpoint). */}
+          из 4 параллельных queries с size=1 (cheap). */}
       <WebhookStatsCards subscriptionId={id} />
 
+      {/* Time-series histogram — backend /stats?bucketBy=hour|day. SVG
+          stacked bars без recharts depend'ы. 24h / 7d toggle. */}
+      <WebhookStatsHistogram subscriptionId={id} />
+
       <div>
         <div className="flex items-center justify-between mb-3">
           <h2 className="font-sans text-title-md text-accent">