Generates natural language summary of timeline.

Provides high-level overview for quick understanding:

• Event count and duration
• Event type breakdown
• Memory trend (growing/stable/shrinking)
• Notable patterns

Designed for LLM consumption to reduce context needed.

Output

%{
  findings: [],
  stats: %{
    summary: "Test: my_test.exs\nDuration: 500ms with 12 events.\nTop events: render (5x), handle_event:click (3x).\nMemory grew during test.",
    event_breakdown: %{"render" => 5, "handle_event:click" => 3, "mount" => 1},
    memory_trend: :growing
  }
}