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/jobs/ops/health_monitor_job.rb

@@ -0,0 +1,33 @@
+module Ops
+  class HealthMonitorJob
+    include Sidekiq::Job
+
+    sidekiq_options retry: 1, queue: "default"
+
+    INTERVAL_SECS = ENV.fetch("OPS_HEALTH_INTERVAL_SECS", "180").to_i
+    REDIS_CHAIN_KEY = "ops:health_monitor:chain"
+    HEARTBEAT_KEY = "ops:health_monitor:last_run"
+
+    def self.ensure_chain
+      return unless redis
+
+      return if redis.get(REDIS_CHAIN_KEY)
+
+      redis.set(REDIS_CHAIN_KEY, "1", ex: INTERVAL_SECS * 2)
+      perform_in(INTERVAL_SECS)
+    end
+
+    def self.redis
+      @redis ||= Redis.new(url: ENV.fetch("REDIS_URL", "redis://localhost:6379/0"))
+    rescue Redis::CannotConnectError
+      nil
+    end
+
+    def perform
+      self.class.redis&.set(HEARTBEAT_KEY, Time.current.to_i, ex: INTERVAL_SECS * 3)
+      Ops::HealthChecks.new.call
+    ensure
+      self.class.perform_in(INTERVAL_SECS)
+    end
+  end
+end