Previously you could've selected a date and time in the past to schedule
publish.
Now we ensure that there is a minimum time and date for scheduled
publishing date picker.
Additionally updated the disabled items to be more visually obvious that
they are disabled:
<img width="404" height="336" alt="image"
src="https://github.com/user-attachments/assets/1f4ea36a-267e-4ae5-91e4-92bb84d7889c"
/>
f63dfad565