Anonymized cohort analysis — aggregate nutrition, weight, and behavioral data

Query anonymized aggregate data across user cohorts. All data is stripped of PII and aggregated to cohort level. Supports filtering by surgery type, months post-surgery, activity level, and detected patterns. Returns aggregate nutrition stats, pattern distribution, food search trends, and restaurant mention frequency. Pass includeHealth: true to also receive the inline health slice (sleep / steps / resting HR / HRV / glucose-in-range / weight loss) — same shape as /research/health-aggregates. For internal research use — no individual user data is ever returned.