If the same common types version is used across all service versions, this decorator should be applied either on the service namespace or on each version enum member. If the common types version is updated in later versions, the decorator should appear on each version enum member.

## Impact

- **Area:** API, SDK

Indicates common-types are not being used, which normally surfaces as other violations too.

## ❌ Incorrect

```tsp
@armProviderNamespace
namespace Microsoft.Contoso;
```

## ✅ Correct

Apply `@armCommonTypesVersion` on the namespace:

```tsp
@armProviderNamespace
@armCommonTypesVersion(Azure.ResourceManager.CommonTypes.Versions.v5)
namespace Microsoft.Contoso;
```

## ✅ Correct (per version)

Apply `@armCommonTypesVersion` on each version enum member:

```tsp
@armProviderNamespace
namespace Microsoft.Contoso;

enum Versions {
  @armCommonTypesVersion(Azure.ResourceManager.CommonTypes.Versions.v4)
  v1,

  @armCommonTypesVersion(Azure.ResourceManager.CommonTypes.Versions.v5)
  v2,
}
```

## Suppression

Suppress only if no common-types are ever used and that is valid; otherwise associate a common-types version with each version in the Versions enum.
