fix: Auto-refresh EventLog every 10s for processing/queued videos

Previously the event log only loaded once when the row was expanded,
so mid-pipeline videos only showed start events. Now the EventLog
component accepts a status prop and polls every 10s when the video is
processing or queued, silently updating without showing a loading spinner.

frontend/src/pages/AdminPipeline.tsx

@@ -215,7 +215,7 @@ function DebugPayloadViewer({ event }: { event: PipelineEvent }) {
 
 // ── Event Log ────────────────────────────────────────────────────────────────
 
-function EventLog({ videoId }: { videoId: string }) {
+function EventLog({ videoId, status }: { videoId: string; status: string }) {
   const [events, setEvents] = useState<PipelineEvent[]>([]);
   const [total, setTotal] = useState(0);
   const [loading, setLoading] = useState(true);
@@ -223,9 +223,10 @@ function EventLog({ videoId }: { videoId: string }) {
   const [offset, setOffset] = useState(0);
   const [viewMode, setViewMode] = useState<"head" | "tail">("tail");
   const limit = 50;
+  const initialLoaded = useRef(false);
 
-  const load = useCallback(async () => {
-    setLoading(true);
+  const load = useCallback(async (silent = false) => {
+    if (!silent) setLoading(true);
     setError(null);
     try {
       const res = await fetchPipelineEvents(videoId, {
@@ -235,10 +236,11 @@ function EventLog({ videoId }: { videoId: string }) {
       });
       setEvents(res.items);
       setTotal(res.total);
+      initialLoaded.current = true;
     } catch (err) {
-      setError(err instanceof Error ? err.message : "Failed to load events");
+      if (!silent) setError(err instanceof Error ? err.message : "Failed to load events");
     } finally {
-      setLoading(false);
+      if (!silent) setLoading(false);
     }
   }, [videoId, offset, viewMode]);
 
@@ -246,6 +248,13 @@ function EventLog({ videoId }: { videoId: string }) {
     void load();
   }, [load]);
 
+  // Auto-refresh when video is actively processing
+  useEffect(() => {
+    if (status !== "processing" && status !== "queued") return;
+    const id = setInterval(() => void load(true), 10_000);
+    return () => clearInterval(id);
+  }, [status, load]);
+
   if (loading) return <div className="loading">Loading events…</div>;
   if (error) return <div className="loading error-text">Error: {error}</div>;
   if (events.length === 0) return <div className="pipeline-events__empty">No events recorded.</div>;
@@ -1056,7 +1065,7 @@ export default function AdminPipeline() {
                     <span>Created: {formatDate(video.created_at)}</span>
                     <span>Updated: {formatDate(video.updated_at)}</span>
                   </div>
-                  <EventLog videoId={video.id} />
+                  <EventLog videoId={video.id} status={video.processing_status} />
                 </div>
               )}
             </div>