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/app/views/shared/_analytics_suppress.html.erb

@@ -0,0 +1,7 @@
+<% if Analytics::Suppress.active?(cookies[Analytics::Suppress::COOKIE_NAME]) %>
+  <meta name="mltv-analytics-suppress" content="1">
+  <div class="mltv-preview-badge" role="status">
+    <span><%= t("ui.analytics_preview.badge") %></span>
+    <%= link_to t("ui.analytics_preview.manage"), admin_analytics_path, class: "mltv-preview-badge__link" %>
+  </div>
+<% end %>