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/models/platform_cost_entry.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+class PlatformCostEntry < ApplicationRecord
+  DEFAULT_LABEL = "Piattaforma produzione"
+
+  validates :month, presence: true
+  validates :label, presence: true, length: { maximum: 120 }
+  validates :amount_cents, numericality: { only_integer: true, greater_than: 0 }
+
+  before_validation :normalize_month
+
+  scope :for_month, ->(date) { where(month: date.to_date.beginning_of_month) }
+  scope :ordered, -> { order(month: :desc, created_at: :desc) }
+
+  def month=(value)
+    if value.is_a?(String) && value.match?(/\A\d{4}-\d{2}\z/)
+      super(Date.strptime(value, "%Y-%m"))
+    else
+      super(value)
+    end
+  end
+
+  def amount_euros
+    amount_cents.to_f / 100.0
+  end
+
+  private
+
+  def normalize_month
+    return if month.blank?
+
+    parsed =
+      case month
+      when Date
+        month
+      when Time, ActiveSupport::TimeWithZone
+        month.to_date
+      when String
+        if month.match?(/\A\d{4}-\d{2}\z/)
+          Date.strptime(month, "%Y-%m")
+        else
+          Date.parse(month)
+        end
+      else
+        Date.parse(month.to_s)
+      end
+    self.month = parsed.beginning_of_month
+  rescue ArgumentError, TypeError
+    errors.add(:month, :invalid)
+  end
+end