[P1] ci-cd: retry path misses ACA state adoption after first failed provision attempt

## Problem
`azd-deploy` fails in a brand-new environment because retry attempt 2 tries to create ACA apps that already exist in Azure but are not present in Terraform state at that moment.

## Type
- bug
- regression

## Evidence
- Workflow run: https://github.com/Azure-Samples/tutor/actions/runs/23124471384
- Job: `provision` (67164738583), step `Provision infrastructure` failed.
- Same run shows:
- attempt 1 transient ACA errors (`Operation expired`), then retry
- attempt 2 errors: `already exists - to be managed via Terraform this resource needs to be imported into the State` for multiple apps (`avatar/chat/configuration/essays/evaluation/lms-gateway/questions/upskilling`).
- Earlier in same job, reconcile step logged several `not found in Azure. Skipping state import.` for those apps before attempt 1.

## Reproduction
1. Trigger `.github/workflows/azd-deploy.yml` with `workflow_dispatch` and `azure_env_name_override=178dev` (or any fresh dev env).
2. Allow first `Provision infrastructure` attempt to hit transient ACA revision failures.
3. Observe retry attempt where Terraform reports `already exists` on ACA apps.

## Acceptance Criteria
- [ ] Before each provision retry, the workflow deterministically imports any ACA app that exists in Azure and is missing from state.
- [ ] State-adoption check includes bounded polling to handle ARM eventual consistency after failed attempt 1.
- [ ] Retry attempt 2 no longer fails with `already exists` for ACA backend apps in fresh env scenarios.
- [ ] Add a step summary block that reports imported/skipped apps per retry for diagnostics.

## Suggested Owner
`platform-quality`