feat: auto-trigger Discord wakeup when slot becomes ONGOING

app/models/calendar.py

@@ -165,6 +165,12 @@ class TimeSlot(Base):
         comment="Lifecycle status of this slot",
     )
 
+    wakeup_sent_at = Column(
+        DateTime(timezone=True),
+        nullable=True,
+        comment="When Discord wakeup was sent for this slot",
+    )
+
     plan_id = Column(
         Integer,
         ForeignKey("schedule_plans.id"),