Fix anomaly banner BU reassignment detail display

- Backend: /anomaly/latest now returns the most recent SIGNIFICANT
  anomaly instead of the absolute latest (non-significant ones are
  useless to the banner which skips them anyway)
- Frontend: expand BU detail time window from 60 minutes to 25 hours
  before the anomaly timestamp to capture changes from the full sync
  cycle (syncs run once per 24h)

backend/routes/ivantiFindings.js

@@ -1384,10 +1384,13 @@ function createIvantiFindingsRouter(db, requireAuth) {
      */
     router.get('/anomaly/latest', async (req, res) => {
         try {
+            // Return the most recent SIGNIFICANT anomaly — the banner only displays
+            // significant events, so returning a non-significant row is useless.
             const { rows } = await pool.query(
                 `SELECT id, sync_timestamp, open_count_delta, closed_count_delta,
                         newly_archived_count, returned_count, classification_json, return_classification_json, is_significant
                  FROM ivanti_sync_anomaly_log
+                 WHERE is_significant = true
                  ORDER BY sync_timestamp DESC LIMIT 1`
             );
             const row = rows[0];

frontend/src/components/pages/AnomalyBanner.js

@@ -248,13 +248,13 @@ export default function AnomalyBanner() {
         setBuExpanded(true);
         try {
             // Fetch BU change records relevant to this anomaly.
-            // Use a generous 60-minute window before sync_timestamp since the drift
-            // checker runs well before the anomaly summary is recorded.
+            // Use a 25-hour window before sync_timestamp to capture changes from
+            // the previous sync cycle (syncs run once per 24h).
             const since = anomaly?.sync_timestamp || '';
             let url;
             if (since) {
                 const sinceDate = new Date(since);
-                sinceDate.setMinutes(sinceDate.getMinutes() - 60);
+                sinceDate.setHours(sinceDate.getHours() - 25);
                 url = `${API_BASE}/ivanti/findings/bu-changes?since=${encodeURIComponent(sinceDate.toISOString())}`;
             } else {
                 url = `${API_BASE}/ivanti/findings/bu-changes?limit=50`;