Old script used deprecated Health.read() with Health.Types.* and .quantity
— every read silently failed in try/catch, so no samples were ever collected.
Rewrote to use Health.queryQuantitySamples() with string type identifiers
and .quantityValue(unit) per current Scripting app docs. Added proper units
(kg, mmHg, count/min, count, percent) for each metric type.
Also adds /scriptable/health-sync.js endpoint to serve the script directly.
