Add yarn caching to workflows that install yarn dependencies

[CamSoper]

Adds cache: 'yarn' to actions/setup-node in the 10 workflows that actually run yarn install or make ensure, with cache-dependency-path pointing at all four yarn.lock files in the repo. On cache hits, yarn runs fully offline, eliminating transient build failures caused by upstream registry errors (HTTP 500, etc.).

Three workflows (bucket-cleanup.yml, bucket-cleanup-testing.yml, pr-closed.yml) install Node but never call yarn, so they are left unchanged.

For three workflows where setup-node appeared before actions/checkout, the checkout step is moved earlier so the lockfiles are present when the cache key is computed.

Mirrors the fix applied in pulumi/registry#9953.

[claude]

Docs Review

This PR adds yarn caching to all 13 GitHub Actions workflows and reorders checkout steps in 3 workflows where setup-node appeared before actions/checkout. The changes are well-structured and consistent.

Infrastructure changes

The approach is technically sound and mirrors the fix applied in pulumi/registry#9953. A few notes:

esc-cli.yml and pulumi-cli.yml correctly use docs/-prefixed paths (e.g., docs/yarn.lock) since these workflows operate with a docs/ working directory or subdirectory. The additional pulumi/sdk/nodejs/yarn.lock entry in pulumi-cli.yml is appropriate for that workflow's scope.

Checkout step reordering in scheduled-test.yml, scheduled-upgrade-programs.yml, and update-search-index.yml is necessary and correctly done — the lockfiles must exist on disk before setup-node can hash them for cache key generation.

Potential concern: BUILD-AND-DEPLOY.md

Per repository review criteria, changes to .github/workflows/ files should be accompanied by a BUILD-AND-DEPLOY.md update if they affect documented workflow behavior. These changes are an optimization (not a new feature), but if BUILD-AND-DEPLOY.md describes the workflow structure or CI/CD process, a brief note about yarn caching being enabled would be helpful for future maintainers. This is a minor suggestion, not a blocker.

Summary

No issues with correctness, consistency, or approach. The PR is clean and focused. If you'd like an additional review or have follow-up questions, feel free to mention @claude.

[pulumi-bot]

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[pulumi-bot]

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[pulumi-bot]

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[Copilot]

Pull request overview

Adds Yarn dependency caching to GitHub Actions workflows that install Node/Yarn dependencies, improving reliability by enabling offline installs when the cache is warm and ensuring lockfiles are available when cache keys are computed.

Changes:

• Added cache: yarn plus cache-dependency-path to actions/setup-node in workflows that run yarn install and/or make ensure.
• Reordered steps in select workflows to run actions/checkout before actions/setup-node so lockfiles are present for cache key computation.
• Included all relevant yarn.lock paths per workflow (including nested checkouts like docs/ and pulumi/ where applicable).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
.github/workflows/update-search-index.yml	Moves checkout before setup-node and enables Yarn caching keyed on lockfiles.
.github/workflows/testing-build-and-deploy.yml	Enables Yarn caching keyed on lockfiles for the testing deploy workflow.
.github/workflows/scheduled-upgrade-programs.yml	Moves checkout earlier and enables Yarn caching keyed on lockfiles.
.github/workflows/scheduled-test.yml	Moves checkout + master fetch earlier and enables Yarn caching keyed on lockfiles.
.github/workflows/pulumi-cli.yml	Enables Yarn caching for the docs + pulumi repo multi-checkout workflow (includes both docs/ and pulumi/ lockfiles).
.github/workflows/pull-request.yml	Enables Yarn caching keyed on lockfiles for PR builds.
.github/workflows/esc-cli.yml	Enables Yarn caching keyed on lockfiles for the docs repo checkout under docs/.
.github/workflows/check-search-urls.yml	Enables Yarn caching keyed on lockfiles for the search URL checker workflow.
.github/workflows/check-links.yml	Enables Yarn caching keyed on lockfiles for the link checker workflow.
.github/workflows/build-and-deploy.yml	Enables Yarn caching keyed on lockfiles for production builds/deploys.