Update a booking policy

Serializer for BookingPolicy CRUD.

Exactly one of calendar, membership_user_id, appointment_type, or is_organization_default must be set on create. Targets are immutable after creation — only the four rule-field seconds are writable on update.

Validation:

• validate() enforces the exactly-one-target invariant on create.
• validate_membership_user_id() checks that the supplied user id belongs to the caller's organization (on create only; targets are immutable on update).
• DuplicateBookingPolicyError from the service is caught and surfaced as a 400 validation error so the client gets a named conflict message.
• The four rule fields use min_value=0 so DRF rejects negatives with a clear field-level 400 before the value reaches the model's PositiveIntegerField constraint.

Write paths (create / update) delegate to BookingPolicyService stored on the serializer context as "booking_policy_service" (the viewset sets it).

Serializer for BookingPolicy CRUD.

Exactly one of calendar, membership_user_id, appointment_type, or is_organization_default must be set on create. Targets are immutable after creation — only the four rule-field seconds are writable on update.

Validation:

• validate() enforces the exactly-one-target invariant on create.
• validate_membership_user_id() checks that the supplied user id belongs to the caller's organization (on create only; targets are immutable on update).
• DuplicateBookingPolicyError from the service is caught and surfaced as a 400 validation error so the client gets a named conflict message.
• The four rule fields use min_value=0 so DRF rejects negatives with a clear field-level 400 before the value reaches the model's PositiveIntegerField constraint.

Write paths (create / update) delegate to BookingPolicyService stored on the serializer context as "booking_policy_service" (the viewset sets it).