🧹 Refine SageMaker resource types: typed SG, instance group resource, cleanup

- Replace securityGroupIdForDomainBoundary string with typed
  securityGroupForDomainBoundary() aws.ec2.securitygroup on domain
- Create aws.sagemaker.clusterInstanceGroup resource with name, instanceType,
  status, currentCount, targetCount, threadsPerCore, iamRole, lifecycleConfig
- Replace cluster instanceGroups() []dict with []aws.sagemaker.clusterInstanceGroup
- Remove deprecated vpcConfig() dict from cluster (vpc() reference is sufficient)
- Rename clusterNode launchTime → launchedAt for naming consistency

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: tas50

providers/aws/resources/aws.lr

@@ -1903,8 +1903,8 @@ private aws.sagemaker.domain @defaults("arn name status") {
   homeEfsFileSystemId() string
   // Default user settings
   defaultUserSettings() dict
-  // Security group ID for domain boundary
-  securityGroupIdForDomainBoundary() string
+  // Security group for domain boundary
+  securityGroupForDomainBoundary() aws.ec2.securitygroup
   // Who manages security groups for inter-app communication: Service or Customer
   appSecurityGroupManagement() string
   // Whether custom tag propagation is supported
@@ -1972,11 +1972,9 @@ private aws.sagemaker.cluster @defaults("arn name status") {
   // IAM role used for cluster operations
   iamRole() aws.iam.role
   // Cluster instance groups
-  instanceGroups() []dict
+  instanceGroups() []aws.sagemaker.clusterInstanceGroup
   // Orchestrator type (EKS or Slurm configuration)
   orchestrator() dict
-  // Deprecated: Use vpc instead. Raw VPC configuration dict
-  vpcConfig() dict
   // VPC associated with this cluster
   vpc() aws.vpc
   // Node recovery mode
@@ -1989,6 +1987,28 @@ private aws.sagemaker.cluster @defaults("arn name status") {
   nodes() []aws.sagemaker.clusterNode
 }
 
+// AWS SageMaker HyperPod cluster instance group
+private aws.sagemaker.clusterInstanceGroup @defaults("instanceGroupName instanceType status") {
+  // Name of the instance group
+  instanceGroupName string
+  // ML instance type for the group
+  instanceType string
+  // Region where the cluster exists
+  region string
+  // Status of the instance group
+  status string
+  // Current number of instances in the group
+  currentCount int
+  // Target number of instances in the group
+  targetCount int
+  // Threads per CPU core
+  threadsPerCore int
+  // IAM execution role for the instance group
+  iamRole() aws.iam.role
+  // Lifecycle configuration
+  lifecycleConfig() dict
+}
+
 // AWS SageMaker HyperPod cluster node
 private aws.sagemaker.clusterNode @defaults("instanceId instanceGroupName instanceType") {
   // Instance ID of the node
@@ -2002,7 +2022,7 @@ private aws.sagemaker.clusterNode @defaults("instanceId instanceGroupName instan
   // Status message for the node
   statusMessage string
   // Time when the node was launched
-  launchTime time
+  launchedAt time
   // Private DNS hostname of the node
   privateDnsHostname string
   // Region where the node exists