Retry failed rolling CI builds once

[Copilot]

Description

Rolling CI builds on main are frequently red because the aggregate probability of at least one low-frequency test flake is high. This change gives the first failed attempt for the current main commit one automatic rerun of failed jobs.

The rolling retry is a separate job in the existing auto-rerun workflow, leaving the PR failure-analysis path unchanged. Before requesting the retry, it verifies that main still points at the failed run's commit so a stale retry cannot replace a newer pending build in the CI concurrency group. Only attempt 1 is eligible.

Red-main issue reporting is coordinated with the retry:

• Main attempt 1 failures are not reported.
• A failed attempt 2 reruns the dependent tracker and files or updates the issue.
• A successful attempt 2 closes any existing issue.
• A fallback reports attempt 1 if the external retry job does not complete successfully.
• Release branch failures remain reportable on attempt 1.

Validation:

• Parsed the changed workflow YAML and validated retry/reporting contracts.
• Syntax-checked the extracted inline GitHub Script blocks with Node.js.
• Exercised current-head retry, stale-head skip, and source-run fallback reporting with mocked GitHub APIs.
• Added focused Infrastructure.Tests coverage for the workflow and issue-reporting contracts. The local test run was blocked because the configured Arcade SDK feed returned HTTP 403; PR CI will run these tests.

Fixes # (issue)

Checklist

• Is this feature complete?
  • Yes. Ready to ship.
  • No. Follow-up changes expected.
• Are you including unit tests for the changes and scenario tests if relevant?
  • Yes
  • No
• Did you add public API?
  • Yes
    • If yes, did you have an API Review for it?
      • Yes
      • No
    • Did you add <remarks /> and <code /> elements on your triple slash comments?
      • Yes
      • No
  • No
• Does the change make any security assumptions or guarantees?
  • Yes
    • If yes, have you done a threat model and had a security review?
      • Yes
      • No
  • No

Created from a Microsoft Teams conversation.