Stabilizza live YouTube/RTMP e fix crash rotazione mobile.

Pipeline YouTube con relay, overlay e publisher sync lato backend; fix GL pauseGlDuringRotation su Android per evitare crash in rotazione durante lo streaming Flutter.

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

backend/app/jobs/overlay_relay_ensure_job.rb

@@ -0,0 +1,80 @@
+# Avvia overlay ffmpeg solo in Sidekiq (un solo job per sessione alla volta).
+class OverlayRelayEnsureJob < ApplicationJob
+  queue_as :default
+
+  LOCK_KEY = "overlay_ensure:lock:%s"
+  LOCK_TTL = 55
+  RETRY_WAIT = 5.seconds
+
+  class << self
+    def enqueue_unique(session_id, attempt: 1, force_restart: false, wait: 0.seconds)
+      key = format(LOCK_KEY, session_id)
+      r = Redis.new(url: ENV.fetch("REDIS_URL", "redis://localhost:6379/0"))
+      return unless r.set(key, "1", nx: true, ex: LOCK_TTL)
+
+      set(wait: wait).perform_later(session_id, attempt, force_restart: force_restart)
+    end
+  end
+
+  def perform(session_id, attempt = 1, force_restart: false)
+    session = StreamSession.find_by(id: session_id)
+    unless session && !session.terminal?
+      clear_lock(session_id)
+      return
+    end
+    return unless session.status.in?(%w[live connecting reconnecting paused])
+
+    begin
+      run_ensure(session, session_id, attempt, force_restart)
+    ensure
+      clear_lock(session_id)
+    end
+  end
+
+  private
+
+  def run_ensure(session, session_id, attempt, force_restart)
+    if Mediamtx::PublisherOnline.video_publishing?(session) && !session.paused?
+      session.go_live! if session.may_go_live?
+      session.reconnect! if session.reconnecting? && session.may_reconnect?
+      Mediamtx::Client.new.set_always_available(session, enabled: false)
+    end
+
+    if force_restart
+      Streams::OverlayRelay.stop(session)
+      Streams::OverlayRelay.terminate_all_session_processes!(session.id)
+    end
+
+    Streams::OverlayRelay.ensure_publishing!(session)
+
+    if Streams::OverlayRelay.healthy?(session)
+      Youtube::LivePipeline.schedule_activate!(session, force: true, wait: 5.seconds)
+      return
+    end
+
+    return if Streams::OverlayRelay.running?(session.id)
+
+    Rails.logger.info("[OverlayRelayEnsureJob] overlay not running, retry session=#{session_id} attempt=#{attempt}")
+    reschedule(session_id, attempt, false) if attempt < 30
+  rescue Mediamtx::Client::Error => e
+    Rails.logger.warn("[OverlayRelayEnsureJob] session=#{session_id}: #{e.message}")
+  end
+
+  def reschedule(session_id, attempt, force_restart)
+    clear_lock(session_id)
+    self.class.enqueue_unique(
+      session_id,
+      attempt: attempt + 1,
+      force_restart: force_restart,
+      wait: RETRY_WAIT
+    )
+  end
+
+  def clear_lock(session_id)
+    redis.del(format(LOCK_KEY, session_id))
+  end
+
+  def redis
+    @redis ||= Redis.new(url: ENV.fetch("REDIS_URL", "redis://localhost:6379/0"))
+  end
+end