feat: add artifactapi_local_terraform resource type

New resource for creating local terraform registries in ArtifactAPI
(repo_type=local, package_type=terraform). These repos host providers
directly rather than proxying an upstream registry.

Schema is minimal: just name and description — no upstream-specific
fields like base_url, caching TTLs, or auth.

internal/provider/resource_local_terraform_test.go

@@ -0,0 +1,125 @@
+package provider
+
+import (
+	"context"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-framework/resource"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+)
+
+func TestLocalTerraformModelToAPI(t *testing.T) {
+	model := localTerraformResourceModel{
+		Name:        types.StringValue("tf-internal"),
+		Description: types.StringValue("Internal terraform registry"),
+	}
+
+	api := localTerraformModelToAPI(model)
+
+	if api.Name != "tf-internal" {
+		t.Errorf("Name: expected tf-internal, got %s", api.Name)
+	}
+	if api.PackageType != "terraform" {
+		t.Errorf("PackageType: expected terraform, got %s", api.PackageType)
+	}
+	if api.RepoType != "local" {
+		t.Errorf("RepoType: expected local, got %s", api.RepoType)
+	}
+	if api.Description != "Internal terraform registry" {
+		t.Errorf("Description: expected 'Internal terraform registry', got %s", api.Description)
+	}
+}
+
+func TestLocalTerraformModelToAPI_EmptyDescription(t *testing.T) {
+	model := localTerraformResourceModel{
+		Name:        types.StringValue("tf-empty"),
+		Description: types.StringValue(""),
+	}
+
+	api := localTerraformModelToAPI(model)
+
+	if api.Name != "tf-empty" {
+		t.Errorf("Name: expected tf-empty, got %s", api.Name)
+	}
+	if api.Description != "" {
+		t.Errorf("Description: expected empty string, got %s", api.Description)
+	}
+	if api.PackageType != "terraform" {
+		t.Errorf("PackageType: expected terraform, got %s", api.PackageType)
+	}
+	if api.RepoType != "local" {
+		t.Errorf("RepoType: expected local, got %s", api.RepoType)
+	}
+}
+
+func TestLocalTerraformAPIToModel(t *testing.T) {
+	api := remoteAPI{
+		Name:        "tf-internal",
+		PackageType: "terraform",
+		RepoType:    "local",
+		Description: "Internal terraform registry",
+		ManagedBy:   "terraform",
+	}
+
+	model := localTerraformAPIToModel(api)
+
+	if model.Name.ValueString() != "tf-internal" {
+		t.Errorf("Name: expected tf-internal, got %s", model.Name.ValueString())
+	}
+	if model.Description.ValueString() != "Internal terraform registry" {
+		t.Errorf("Description: expected 'Internal terraform registry', got %s", model.Description.ValueString())
+	}
+}
+
+func TestLocalTerraformRoundTrip(t *testing.T) {
+	original := localTerraformResourceModel{
+		Name:        types.StringValue("roundtrip-local"),
+		Description: types.StringValue("Round trip test"),
+	}
+
+	api := localTerraformModelToAPI(original)
+	result := localTerraformAPIToModel(api)
+
+	if result.Name.ValueString() != original.Name.ValueString() {
+		t.Errorf("Name: expected %s, got %s", original.Name.ValueString(), result.Name.ValueString())
+	}
+	if result.Description.ValueString() != original.Description.ValueString() {
+		t.Errorf("Description: expected %s, got %s", original.Description.ValueString(), result.Description.ValueString())
+	}
+}
+
+func TestLocalTerraformResource_Metadata(t *testing.T) {
+	r := NewLocalTerraformResource()
+	req := resource.MetadataRequest{ProviderTypeName: "artifactapi"}
+	var resp resource.MetadataResponse
+	r.Metadata(context.Background(), req, &resp)
+	if resp.TypeName != "artifactapi_local_terraform" {
+		t.Errorf("expected artifactapi_local_terraform, got %s", resp.TypeName)
+	}
+}
+
+func TestLocalTerraformResource_Schema(t *testing.T) {
+	r := NewLocalTerraformResource()
+	req := resource.SchemaRequest{}
+	var resp resource.SchemaResponse
+	r.Schema(context.Background(), req, &resp)
+
+	expectedAttrs := []string{"name", "description"}
+	for _, attr := range expectedAttrs {
+		if _, ok := resp.Schema.Attributes[attr]; !ok {
+			t.Errorf("missing expected attribute: %s", attr)
+		}
+	}
+
+	if len(resp.Schema.Attributes) != len(expectedAttrs) {
+		t.Errorf("expected %d attributes, got %d", len(expectedAttrs), len(resp.Schema.Attributes))
+	}
+}
+
+func TestNewLocalTerraformResource_Type(t *testing.T) {
+	r := NewLocalTerraformResource()
+	_, ok := r.(*localTerraformResource)
+	if !ok {
+		t.Error("expected *localTerraformResource")
+	}
+}