Refactor to fix memory leaks

Memory Leak Fixes & Refactoring

EGPProtocol

• Fixed incorrect condition in _create_id_to_request pop operation

MagicLinkLayerProtocol

• Replaced dynamic namedtuple with explicit QueueItem class for better type annotations
• Introduced Delivery object to track deliveries in MagicDistributor
• Removed redundant self-calling self._defer_handle_next() when capacity is zero

MagicDistributor

• Replaced event-based bookkeeping with dedicated Delivery and NodeDelivery objects
• Added properties:
  • node_deliveries list to Delivery
  • in_process flag to both Delivery and NodeDelivery
  • state_delivery_evt and label_delivery_evt to NodeDelivery
• Consolidated multiple event tracking properties into _deliveries and _archived_deliveries
• Modified signatures:
  • add_delivery(): now returns Delivery object instead of event
  • abort_delivery(): now accepts Delivery object instead of event
  • abort_all_delivery(): now returns Delivery objects instead of NodeDelivery objects

MagicQLink

• Updated to accommodate signature changes in MagicDistributor.abort_all_delivery()