BE-001: Add unique constraint on (user_id, device_id, metric_type, measured_at) in health_metrics table

Track: 1 — MVP
Section: 1.1 Device Sync — Deduplication
Status: [ ] Todo
Repo: backend-api
Branch: feature/BE-001-health-metrics-unique-constraint

Done When

Migration runs. Inserting a duplicate row returns a DB conflict error instead of creating a second row

Notes

No notes yet.