Aggiunge monitoraggio ops: health check, log scanner, dashboard e notifiche.

Introduce incidenti con dedup, job Sidekiq ogni 3 min, scan log cron, /up/deep,
dashboard /admin/ops e push ntfy; include Sentry opzionale e fix test suite.

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

backend/app/controllers/admin/dashboard_controller.rb

@@ -13,7 +13,22 @@ module Admin
     def metrics
       host = HostMetrics.new.sample!
       stats = DashboardStats.new.call
-      render json: { host: host, stats: stats, at: Time.current.iso8601 }
+      render json: {
+        host: host,
+        stats: stats,
+        ops_summary: ops_summary,
+        at: Time.current.iso8601
+      }
+    end
+
+    private
+
+    def ops_summary
+      {
+        open_critical: Ops::Incident.critical_open.count,
+        open_warning: Ops::Incident.open.where(severity: "warning").count,
+        open_total: Ops::Incident.open.count
+      }
     end
   end
 end