Returns comprehensive metadata for a single key including:

• Lifecycle information (status, created/expires timestamps)
• Usage tracking (usage count, limits)
• Algorithm details (kty, alg)
• Capability flags (exportable, origin, restricted, keyOps)

This endpoint is suitable for administrative dashboards, key inventory
systems, and compliance audits where cryptographic material exposure
is unnecessary.

Note: To retrieve the public key material, use the admin-api export endpoint
GET /api/v3/admin/tenants/{tenantId}/keys/{kid}/export which enforces exportable flag validation.