Get data quality metrics for award flight availability data.

Returns: { "summary": { "total_records": integer, "avg_freshness_score": float, "total_sources": integer }, "programs": [ { "source": "airline_code", "record_count": integer, "last_updated": "2024-01-01T00:00:00Z", "api_last_updated": "2024-01-01T00:00:00Z", "earliest_date": "2024-01-01", "latest_date": "2024-12-31", "freshness_score": integer (0-100) }, ... ] }