Handle API operations that support either account or zone scope #33

Problem

Some generated operations can target either an account or a zone. The CLI needs deterministic scope selection without exposing duplicate or confusing commands.

Expected behavior

• When no zone is provided, use the account-scoped operation.
• When --zone is provided, use the zone-scoped operation.
• Fail clearly when the required account or zone context cannot be resolved.

Acceptance criteria

• Help documents how scope is selected.
• Dry-run output shows the resolved scope and request path.
• Tests cover explicit zone scope, default account scope, and missing context.