Aggiunge grafico andamento visite in admin Analytics.

Serie giornaliera di pageview/click/movimenti nel periodo filtrato, sopra la tabella pagine.

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

backend/spec/requests/admin/analytics_spec.rb

@@ -33,6 +33,25 @@ RSpec.describe "Admin analytics", type: :request do
     expect(response.body).to include("/prezzi")
     expect(response.body).to include("12")
     expect(response.body).to include("40")
+    expect(response.body).to include("chart-analytics-trend")
+    expect(response.body).to include("adminAnalyticsTrend")
+  end
+
+  it "mostra il trend anche su più giorni" do
+    AnalyticsPageStat.create!(
+      day: 1.day.ago.to_date,
+      page_path: "/prezzi",
+      device: "desktop",
+      pageview_count: 5,
+      scroll_samples: 0,
+      scroll_sum_pct: 0,
+      max_scroll_pct: 0
+    )
+
+    get admin_analytics_path, params: { from: 2.days.ago.to_date, to: Time.zone.today }
+    expect(response).to have_http_status(:ok)
+    expect(response.body).to include("\"pageviews\":5")
+    expect(response.body).to include("\"pageviews\":12")
   end
 
   it "mostra la heatmap di una pagina con tab dispositivo" do