The type of permissions granted to all users in the organization for this resource.

Allocations (single and group) always have at least viewer public access, so it cannot be cleared:

• If public is omitted, the stored value is kept.
• An empty string ("") is accepted for backward compatibility and is treated as viewer.
• An explicit null is rejected with 400 Bad Request.

For Reports, Budgets, and Alerts, an omitted or null value sets public to null (no public access).