chore: Add workflow to override visual regression test results

[jperals]

Description

This is a prerequisite to making the visual regression test workflow mandatory.

Ticket: D417180663

Doc: J5RmAnz6YwPa

How has this been tested?

On this PR, two new checks are run:

• Check for commit override
• Visual regression result

On a PR without visual changes like this one, there are no functional differences.

Once this change is merged, it will be possible to test the actual override workflow (GitHub workflows can only be triggered from comments or actions if they are in main).

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.66%. Comparing base (0c1c9fd) to head (c676f59).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4954   +/-   ##
=======================================
  Coverage   97.66%   97.66%           
=======================================
  Files         959      959           
  Lines       31345    31354    +9     
  Branches    11579    11583    +4     
=======================================
+ Hits        30614    30623    +9     
+ Misses        724      685   -39     
- Partials        7       46   +39     

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[Copilot]

🟡 Changes recommended

The override workflow is missing required token permissions for its Pulls API call, and the documentation currently claims PR commenting behavior that the workflow does not implement.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Pull request overview

Adds a per-commit override mechanism for visual regression results so maintainers can explicitly approve intentional visual diffs and allow the required “Visual regression result” check to pass without rebuilding baselines.

Changes:

• Adds a new Override visual regression workflow that can be triggered via PR comment or manual dispatch and posts a visual-regression-override commit status.
• Updates the reusable visual regression workflow to check for the override status and skip expensive screenshot comparison when overridden.
• Updates the deploy workflow to surface a dedicated required “Visual regression result” gate and documents the new override flow.

File summaries

File	Description
docs/RUNNING_TESTS.md	Documents the override-based approval flow for intentional visual diffs.
.github/workflows/visual-regression.yml	Adds a commit-status override check and skips visual shards when overridden.
.github/workflows/visual-regression-override.yml	Introduces the workflow that applies the per-commit override status and reruns failed deploy jobs.
.github/workflows/deploy.yml	Adds statuses read permission, passes commit SHA into the visual workflow, and adds a required “Visual regression result” gate.

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 3
• Review effort level: Lite

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[Copilot]

🟡 Changes recommended

Skipping the visual shard job on override can still leave the reusable workflow failing due to downstream report jobs running without artifacts, which undermines the intended “override makes it green” behavior.

Once you've addressed the issues Copilot identified, you can request another Copilot review.

Review details

• Files reviewed: 4/4 changed files
• Comments generated: 5
• Review effort level: Lite