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

backend/server.js

@@ -1156,6 +1156,20 @@ app.get('/api/stats', requireAuth(), async (req, res) => {
     }
 });
 
+// Serve frontend build (for testing/production — serves React SPA)
+const frontendBuild = path.join(__dirname, '..', 'frontend', 'build');
+if (fs.existsSync(frontendBuild)) {
+    app.use(express.static(frontendBuild));
+    // SPA fallback — serve index.html for any non-API route
+    app.use((req, res, next) => {
+        if (!req.path.startsWith('/api/') && !req.path.startsWith('/uploads/')) {
+            res.sendFile(path.join(frontendBuild, 'index.html'));
+        } else {
+            next();
+        }
+    });
+}
+
 // Start server
 app.listen(PORT, () => {
     console.log(`CVE API server running on http://${API_HOST}:${PORT}`);