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/helpers/admin_helper.rb

@@ -1,4 +1,21 @@
 module AdminHelper
+  def format_euros(cents, precision: 2)
+    return I18n.t("admin.common.dash") if cents.nil?
+
+    format("%.*f €", precision, cents.to_f / 100.0)
+  end
+
+  def format_hours(hours)
+    return I18n.t("admin.common.dash") if hours.nil? || hours.to_f <= 0
+
+    total_minutes = (hours.to_f * 60).round
+    format_duration_minutes(total_minutes)
+  end
+
+  def admin_month_label(month)
+    I18n.l(month, format: "%B %Y")
+  end
+
   def format_bytes(bytes)
     return "—" if bytes.nil?