Explicitly grant or withdraw group health insights consent

Off by default and separate from health storage and product-usage analytics. Granting means your sex, age group, and the height and weight you saved yourself may be counted in anonymised group totals shown to your company or MedBuk+ partners; they never see you, and Apple Health data is never used. Withdrawal takes effect immediately and keeps your readings. Each change is timestamped and audited.

curl -X PUT "https://example.com/v1/me/group-health-insights-consent" \  -H "Content-Type: application/json" \  -d '{    "enabled": true,    "noticeVersion": "2026-10-04"  }'

{  "enabled": true,  "consentedAt": "2019-08-24T14:15:22Z",  "noticeVersion": "2026-10-04",  "currentNoticeVersion": "2026-10-04"}