now with a working countdowntimer for each dewar

backend/app/models.py

@@ -156,6 +156,5 @@ class LogisticsEvent(Base):
     slot_id = Column(Integer, ForeignKey('slots.id'))   # corrected table name
     event_type = Column(String, index=True)
     timestamp = Column(DateTime, default=datetime.utcnow)
-    action_details = Column(String)
     dewar = relationship("Dewar", back_populates="events")
     slot = relationship("Slot", back_populates="events")