Scenario 8: Edge-Adjacent Events

Events that touch but don't overlap: Event A (10:00-11:00) and Event B (11:00-12:00). A ends exactly when B starts, so they should NOT stack.

Expected Result:
Event A: stackLevel=0 (stacked)
Event B: stackLevel=0 (stacked)

10:00 - 11:00

Scenario 8: Event A

11:00 - 12:00

Scenario 8: Event B