{"coverage": {"first_observed_day": 21, "last_observed_day": 123, "missing_days": [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20], "days_without_measurements": [38, 44], "days_with_weight": [50, 51], "days_with_sleep": [22, 23, 50]}, "observations": [{"date": "2026-04-14", "weight_kg": 68.16, "sleep_hours": 7.0, "calories_kcal": 2400}, {"date": "2026-04-15", "weight_kg": 68.46, "sleep_hours": null, "calories_kcal": null}], "weekly_weight_trend": [{"week_start": "2026-04-13", "average_weight_kg": 68.31, "sample_count": 2}]}