-- v1.3.3: Add OXYGEN_SATURATION (SpO2) measurement type
--
-- Closes #109 feature request. Single-value type (no per-context split like
-- BLOOD_GLUCOSE — context goes into the free-text `notes` field).
--
-- Storage unit: percent (0..100). Plausibility range 50..100 in
-- src/lib/validations/measurement.ts (anything below 50% is incompatible with
-- sustained life and almost certainly a faulty sensor).
--
-- Withings devices that support SpO2 (e.g. ScanWatch) report measure type 54.
-- See src/lib/withings/client.ts MEASURE_TYPE_MAP.
ALTER TYPE "measurement_type" ADD VALUE IF NOT EXISTS 'OXYGEN_SATURATION';