chore(deps): update actions/checkout action to v6

[thomhurst]

This PR contains the following updates:

Package	Type	Update	Change
actions/checkout	action	major	v4 → v6
actions/checkout	action	major	v5 → v6

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Release Notes

actions/checkout (actions/checkout)

v6

Compare Source

• Persist creds to a separate file by @​ericsciple in #​2286
• Update README to include Node.js 24 support details and requirements by @​salmanmkc in #​2248

v5

Compare Source

• Port v6 cleanup to v5 by @​ericsciple in #​2301

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This PR has been generated by Renovate Bot.

[Copilot]

Pull request overview

This PR updates the actions/checkout GitHub Action from v4 to v6 across all workflow files. This is a major version upgrade that includes important changes such as persisting credentials to a separate file and updated Node.js support (Node.js 24). The update has been comprehensively applied across all 11 workflow files that use the checkout action.

Key Changes

• Upgraded actions/checkout from v4 to v6 across all GitHub Actions workflows
• Ensures consistent use of the latest checkout action version throughout the repository
• Applies security and Node.js compatibility improvements from v6

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/workflows/claude.yml	Updated checkout action to v6 in the Claude Code workflow
.github/workflows/claude-code-review.yml	Updated checkout action to v6 in the Claude Code Review workflow
.github/workflows/codeql.yml	Updated checkout action to v6 in the CodeQL Advanced workflow
.github/workflows/deploy-pages-test.yml	Updated checkout action to v6 in the test deployment workflow
.github/workflows/deploy-pages.yml	Updated checkout action to v6 in the production deployment workflow
.github/workflows/dotnet-build-different-locale.yml	Updated checkout action to v6 in the locale testing workflow
.github/workflows/dotnet.yml	Updated checkout action to v6 in the main .NET workflow
.github/workflows/generate-readme.yml	Updated checkout action to v6 in the README generation workflow
.github/workflows/speed-comparison.yml	Updated checkout action to v6 in all 4 jobs (build-test-artifacts, run-time-benchmarks, build-time-benchmarks, process-and-upload-benchmarks)