Schema unification across annotation files so HF's auto-loader stops failing with CastError. Specifically:
- event_verification/warehouse_near_miss: wrap list into bcq dict, rename video_id -> video, add system_prompt.
- vqa: pad each entry with the union of fields across all 5 files.
- temporal_localization: pad each entry with the union of fields across all 3 files.
- data/README.md updated to reflect the unified EV schema.