Add compute resolution in job submit

[saanikaguptamicrosoft]

No description provided.

[Copilot]

Pull request overview

This PR implements real compute-name resolution for the azure.ai.customtraining extension by calling the Azure Resource Manager (ARM) control plane to translate a friendly compute name into a full ARM resource ID during job submission.

Changes:

• Implement ARM-backed compute resolution (HTTP GET + token acquisition) and return the compute resource id.
• Wire job submission to construct the compute resolver using subscription ID and resource group from the azd environment.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

File	Description
cli/azd/extensions/azure.ai.customtraining/internal/service/compute_resolver.go	Replaces the stub compute resolver with an ARM GET implementation that extracts the compute ARM ID.
cli/azd/extensions/azure.ai.customtraining/internal/cmd/job_submit.go	Passes env-derived subscription/resource group/account + credential into the compute resolver used during job submission.

Comments suppressed due to low confidence (1)

cli/azd/extensions/azure.ai.customtraining/internal/cmd/job_submit.go:62

• subscriptionID/resourceGroup are now required for compute-name resolution, but this command only validates accountName/projectName. In implicit init flows, AZURE_RESOURCE_GROUP_NAME is intentionally not set, which will cause compute resolution to fail later with a confusing ARM 404. Add a preflight validation for missing subscriptionID/resourceGroup and return a clear error (e.g., prompt to run azd ai training init or provide a full ARM compute ID in the YAML).

			subscriptionID := envValues[utils.EnvAzureSubscriptionID]
			resourceGroup := envValues[utils.EnvAzureResourceGroup]

			if accountName == "" || projectName == "" {
				return fmt.Errorf("environment not configured. Run 'azd ai training init' first")
			}