Disconnect an outbound integration

Disconnects the active HubSpot or Klaviyo account using an explicit retain-versus-remove policy for app-owned provider data. With remove, provider cleanup must succeed before the connection is revoked. With retain, existing provider data remains while future enrichment and monitoring stop. Requires 'account' scope and an owner/admin member. After disconnection, a fresh OAuth authorization may connect this provider account to another organization. The new association has a separate connection ID; historical jobs, usage charges, and identity licences remain with their original organization.