kotlinx-datetime-helper-kit

Wrap the multiplatform date-time library's instant-to-local-date-time conversions in a few named helpers — now, epoch converters, comparisons, a shifted-window helper and a relative "time ago" formatter — so call sites read as intent instead of ceremony. Covers what each wrapper must pin explicitly, and the trap family behind it: a helper reading one time zone while persistence reads another, arithmetic done on…