emoji_eventsMerge overlapping intervals

Booking systems often need to merge busy time slots. Write merge(intervals) that takes a list of (start, end) pairs and returns a new list where overlapping or touching intervals are merged, sorted by start.

• [(1, 3), (2, 6), (8, 10)] becomes [(1, 6), (8, 10)].
• Touching counts as overlapping: [(1, 2), (2, 4)] becomes [(1, 4)].
• The input may be unsorted; don't modify it.

Acceptance criteria

• An empty list returns [].
• The tests at the bottom print All tests passed.