appointmentEventUserConflicts
For each user, returns the existing events that would conflict if they were
assigned an appointment in the given window. Reads from the Postgres
source-of-truth so callers always see post-mutation freshness. Time-off
conflicts are normalized to blocked.
Arguments
DateTime!Exclusive end of the conflict window
IDAn appointment event to omit from consideration, e.g. the appointment currently being edited
DateTime!Inclusive start of the conflict window
[ID!]!The users whose schedules should be checked
Returns
[AppointmentEventUserConflict!]!A scheduling conflict a user would have if assigned an appointment in the given window