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/spec/requests/public/regia_spec.rb

@@ -26,6 +26,15 @@ RSpec.describe "Public regia", type: :request do
   end
 
   it "mette in pausa e riprende la diretta" do
+    mtx = instance_double(
+      Mediamtx::Client,
+      set_always_available: true,
+      set_path_recording: true,
+      delete_path: true,
+      list_paths: []
+    )
+    allow(Mediamtx::Client).to receive(:new).and_return(mtx)
+
     token = Sessions::RegiaAccess.new(session).issue_token!
     post public_regia_pause_path(token)
     expect(response).to have_http_status(:ok)