Live2TrackingDataConverter

Adapter that converts BLive 2.0 SSAI tracking API responses into SDK ad models.

Consistent with the web player's packages/ssai/src/live2/convert.js:

• eventType: "clickthrough" → first beacon URL used as click-through
• eventType: "click" → all beacon URLs used as click tracking
• Standard VAST event types → creative-level tracking events
• eventType: "impression" → ad-level tracking events

Pure function with no side effects — fully unit-testable.