engineering: use tar+zstd for win32 node_modules cache

[joaomoreno]

from @tmm1:

this is significantly faster in my tests, down to 60s vs 120-180s before in the Extract node_modules phase
GHA and Azure Pipelines images have tar.exe and zstandard bundled since a few years ago
(will need to bump cachesalt if merging, to invalidate old cache)
cc @lszomoru @deepak1556

[Copilot]

Pull request overview

This PR replaces 7-Zip compression with tar+zstd for Windows node_modules caching to significantly improve CI/CD performance. According to the PR description, this reduces the Extract node_modules phase from 120-180 seconds to 60 seconds. Both tar.exe and zstandard are bundled in GitHub Actions and Azure Pipelines Windows images, making this change feasible without additional tooling requirements.

Changes:

• Replaced all 7z.exe commands with tar+zstd commands across GitHub Actions and Azure Pipelines workflows
• Changed cache file extension from .7z to .tzst
• Updated .cachesalt timestamp to invalidate existing caches

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
.github/workflows/pr-win32-test.yml	Updated extraction and creation commands to use tar+zstd instead of 7z
.github/workflows/pr-node-modules.yml	Updated Windows job creation command to use tar+zstd instead of 7z
build/azure-pipelines/win32/steps/product-build-win32-compile.yml	Updated extraction and creation commands to use tar+zstd instead of 7z
build/azure-pipelines/win32/product-build-win32-node-modules.yml	Updated creation command to use tar+zstd instead of 7z
build/.cachesalt	Bumped timestamp to invalidate old 7z-based caches

[rzhao271]

This change broke CI for #291731. Reverting.