Retrieves the rotation policy for a specific tenant.
This policy controls algorithm transitions during key rotation operations.

Rotation policies enforce rules such as:
• Operations subset: new key must support operations of original
• No downgrade: prevent transitions to weaker algorithms
• Classical to PQC: control quantum-safe transitions
• Algorithm family: restrict changes within same family

The 'includeInherited' parameter controls the response:
• false: Returns only custom tenant policy (404 if not configured)
• true: Returns custom policy if exists, otherwise deployment policy