Function select_enrollment_capacity 

pub const fn select_enrollment_capacity(
    request: &EnrollmentRequest,
    current: EnrollmentCapacityCounters,
) -> EnrollmentCapacityDecision

Applies the fixed enrollment runtime-capacity order atomically.

The order is identity Server, identity Conversation, LiveReceiptServer, ProvenanceServer, then ProvenanceConversation. A refusal exposes only the first full scope; success carries every post-increment counter together.