BE-017: Fix GET /health/summary — aggregate steps as SUM, HR as AVG for given date

Track: 1 — MVP
Section: 1.6 Health Summary API
Status: [ ] Todo
Repo: backend-api
Branch: feature/BE-017-fix-health-summary-aggregation

Done When

Insert 3 step records (1000, 2000, 3000) for today. GET /health/summary?date=today returns steps: 6000. Insert 3 HR records (60, 80, 100) → returns avg_heart_rate: 80

Notes

No notes yet.