Admin analytics: heatmap per device, anteprima staff e analisi costi.

Separa heatmap mobile/desktop, opt-out analytics per operatori, dashboard costi con KPI e trend mensili.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/public/admin.css

@@ -693,6 +693,13 @@ body.admin-body {
   background: #3a1515;
 }
 
+.admin-device-tab-count {
+  margin-left: 0.35rem;
+  padding: 0 0.35rem;
+  font-size: 0.75rem;
+  color: var(--muted);
+}
+
 .admin-locale-panel {
   display: grid;
   gap: 0.75rem;
@@ -793,6 +800,12 @@ body.admin-body {
   gap: 0.6rem;
 }
 
+.admin-analytics-preview__status {
+  margin: 0 0 0.75rem;
+  color: #a5f0b8;
+  font-size: 0.9rem;
+}
+
 .admin-filter-count {
   font-size: 0.85rem;
 }