Add Kubernetes search Recipe - Terraform

Overview of the Resource type and Recipe

Radius.AI/search only has an Azure recipe today. Explore a Kubernetes Recipe in Terraform.

Design consideration

Same API-compatibility caveat as the Bicep issue — Azure AI Search's proprietary API has no drop-in in-cluster equivalent. Decide engine/approach first.

Acceptance criteria (if we proceed)

1. A Kubernetes Terraform recipe at AI/search/recipes/kubernetes/terraform/ provisioning the chosen engine.
2. Emits the Radius result object with the resource type's outputs.
3. Recipe entry added to the default Kubernetes recipe pack (recipepack/kubernetes/default-recipepack.bicep).
4. README; manual testing with make test-recipe.

Additional context

Example: Data/postgreSqlDatabases/recipes/kubernetes/terraform/; contribution guide docs/contributing/contributing-resource-types-recipes.md.