Returns the entity types, actions, statuses, crypto operation types and
integration surfaces the audit queries on THIS caller's plane accept, so a client
never authors a filter value the server would reject or answer with a permanently
empty page.

The projection is plane-scoped. A caller holding any audit.platform.* scope receives the PLATFORM projection; every other

caller receives the TENANT projection, which is scoped on the governance
disclosure set rather than on the wider tenant input-validation set — so

platform-owned families such as PLATFORMSETTING are never offered to
a tenant auditor even though a tenant-plane query would accept them.

It is also source-scoped. Each dimension belongs to an event source and

is projected only when the caller's scopes admit that source:
operationTypes to crypto; entityTypes,
actions and integrations to admin;
statuses is shared by all three. A dimension the caller may not read

comes back as an empty array, and admittedSources names the sources
it was projected for.

Every offered value is accepted by this plane's queries; the reverse does not hold, and deliberately so.