feat: per-BU trend lines in counts history chart

- Create ivanti_counts_history_by_bu table (bu_ownership, state, count per sync)
- Sync writes per-BU snapshot alongside global history on each sync
- Seed table with current counts for immediate first data point
- GET /counts/history accepts ?teams param — queries per-BU table when filtered
- IvantiCountsChart accepts teamsParam prop, re-fetches on scope change
- ReportingPage passes getActiveTeamsParam() to the chart
- Historical per-BU data accumulates from this point forward
- Global history (no filter) still uses the original aggregate table

frontend/src/components/pages/ReportingPage.js

@@ -5187,8 +5187,16 @@ export default function VulnerabilityTriagePage({ filterDate, filterEXC }) {
     }, []); // eslint-disable-line
 
     // Re-fetch counts when admin scope changes (per-BU counts from Postgres)
+    // Silent fetch — no loading spinner, just update the numbers
     useEffect(() => {
-        fetchCounts();
+        const teamsParam = getActiveTeamsParam();
+        const url = teamsParam
+            ? `${API_BASE}/ivanti/findings/counts?teams=${encodeURIComponent(teamsParam)}`
+            : `${API_BASE}/ivanti/findings/counts`;
+        fetch(url, { credentials: 'include' })
+            .then(r => r.ok ? r.json() : null)
+            .then(data => { if (data) setStatusCounts({ open: data.open ?? 0, closed: data.closed ?? 0 }); })
+            .catch(() => {});
     }, [adminScope]); // eslint-disable-line
 
     // Set/clear a single column filter
@@ -5786,7 +5794,7 @@ export default function VulnerabilityTriagePage({ filterDate, filterEXC }) {
                 Panel 1.5 — Open vs Closed trend over time
             ---------------------------------------------------------------- */}
             {metricsTab === 'ivanti' && <AnomalyBanner />}
-            {metricsTab === 'ivanti' && <IvantiCountsChart />}
+            {metricsTab === 'ivanti' && <IvantiCountsChart teamsParam={getActiveTeamsParam()} />}
 
             {/* ----------------------------------------------------------------
                 Panel 2 — Findings table