fix: aggregate ingestion throughput chart by time bucket

The throughput API returns one row per source_type per time bucket,
but the chart was mapping each row as a separate bar. With 5 source
types × 24 hours, the bars were tiny and overlapping. Now aggregates
completed/failed/items across source types per time bucket so the
chart shows meaningful totals.

frontend/src/pages/OpsIngestion.tsx

@@ -11,15 +11,22 @@ export function OpsIngestionPage() {
 
   if (tpLoading) return <LoadingSpinner />;
 
-  const chartData = (throughput ?? []).map((row: unknown) => {
-    const r = row as Record<string, unknown>;
-    return {
-      time: r.bucket_start ? new Date(r.bucket_start as string).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' }) : '',
-      completed: Number(r.completed ?? 0),
-      failed: Number(r.failed ?? 0),
-      items: Number(r.items_fetched ?? 0),
-    };
-  });
+  const chartData = (() => {
+    const buckets = new Map<string, { time: string; completed: number; failed: number; items: number }>();
+    for (const row of throughput ?? []) {
+      const r = row as Record<string, unknown>;
+      const time = r.bucket_start
+        ? new Date(r.bucket_start as string).toLocaleTimeString([], { hour: '2-digit', minute: '2-digit' })
+        : '';
+      if (!time) continue;
+      const existing = buckets.get(time) ?? { time, completed: 0, failed: 0, items: 0 };
+      existing.completed += Number(r.completed ?? 0);
+      existing.failed += Number(r.failed ?? 0);
+      existing.items += Number(r.items_fetched ?? 0);
+      buckets.set(time, existing);
+    }
+    return Array.from(buckets.values());
+  })();
 
   const s = (summary ?? {}) as Record<string, unknown>;