[P2] ci-cd: provision-service-infra backend initialization failure

[Cataldir]

Problem

provision-service-infra matrix jobs fail in azd-deploy with Terraform backend initialization errors.

Evidence

• Run: https://github.com/Azure-Samples/tutor/actions/runs/23241035241
• Failing jobs: all provision-service-infra (*)
• Representative log error:
  • Error: Backend initialization required, please run "terraform init"
  • Reason: Initial configuration of requested backend "azurerm"

Reproduction

1. Trigger .github/workflows/azd-deploy.yml with release_tier=dev and azure_env_name_override=108dev.
2. Wait for provision-service-infra matrix.
3. Observe backend initialization failures in step Apply changed service-edge stack.

Impact

• User impact: High (pipeline fails despite successful foundation + backend deploy).
• Blast radius: CI/CD release path for infra reconciliation and APIM policy drift remediation.

Acceptance Criteria

• provision-service-infra succeeds for all matrix services in 108dev.
• Terraform backend strategy is consistent with state/import operations used in job.
• If backendless mode is chosen, no state/import commands depend on azurerm backend.
• Full azd-deploy workflow completes successfully in dev (including post-deploy-guardrails).