Free/Busy and Availability

CalDAV free/busy queries work for local principals and scheduling flows.

Availability follows RFC 7953. A principal can publish working hours by storing a VAVAILABILITY document in the calendar-availability property of their scheduling inbox:

PROPPATCH /dav/calendars/{owner}/inbox/

Free/busy responses mark time outside those windows as BUSY-UNAVAILABLE.

This lets clients distinguish explicit busy events from unavailable working-hour boundaries when they support availability.