fix: pick active date by scroll direction in resource mode

[anton-patrushev]

Summary

• Track previous horizontal scroll offset in resource mode and use direction of travel to pick the visible day:
  • forward → latest visible date (existing behaviour)
  • backward → earliest visible date
• Fixes lag where backward swipes kept reporting the day being scrolled AWAY from until it fully exited the viewport, making custom headers visibly trail the swipe.

Ported from core-mobile patch @howljs+calendar-kit+2.5.6+025+direction-aware-resource-scroll-active-date.

Stacked on top of #25.

Test plan

• Resource mode, swipe forward; verify active date advances as before.
• Resource mode, swipe backward; verify active date updates immediately to earliest visible day.
• Verify haptic feedback still fires on day changes.