Describe the bug
When my local date is Feb 6, I cannot book meeting slots that are still valid on Feb 5 in PST once my local time passes 12:00 PM.

These PST slots should remain bookable until Feb 5 ends in PST, but Cal.com blocks them prematurely based on my local date/time.

Steps to Reproduce
1. Booker timezone: IST (UTC+5:30) (replace with yours if different)
2. Host timezone: PST (UTC-8)
3. Current time for booker: Feb 6, after 12:00 PM (IST)
4. Host still has valid availability on Feb 5 (PST)
5. Attempt to book any remaining Feb 5 PST slot

Expected Behavior
Slots on Feb 5 PST should remain bookable until Feb 5 ends in PST, regardless of the booker already being on Feb 6.

Actual Behavior
All remaining Feb 5 PST slots become unavailable once the booker passes 12 PM on Feb 6, even though the host’s date has not ended.

Environment
• Platform: Cal.com (cloud)
• Browser: (Chrome / Safari)
• OS: (macOS / Windows)

Additional Context
This appears to be an issue where booking availability is incorrectly restricted using the booker’s local date instead of the host’s timezone date.

Likely root cause

Availability cutoff seems to be calculated using booker_now() instead of host_now() when validating same-day slots across timezones.