Scenario 3: Nested Stacking

Description

Progressive nesting pattern: Event A (09:00-15:00) contains B (10:00-13:00), B contains C (11:00-12:00), and C overlaps with D (12:30-13:30). Tests correct stack level calculation for nested events.

Expected Result:
Event A: stackLevel=0 (stacked)
Event B: stackLevel=1 (stacked)
Event C: stackLevel=2 (stacked)
Event D: stackLevel=2 (stacked)

09:00 - 15:00

Scenario 3: Event A

10:00 - 13:00

Scenario 3: Event B

11:00 - 12:00

Scenario 3: Event C

12:30 - 13:30

Scenario 3: Event D