fix(NODE-6642): include install script in published files

[axelonet]

Description

Summary of Changes

Fix `npm install @mongodb-js/zstd --build-from-source` failing because the install script referenced a file that was not shipped in the tarball

Notes for Reviewers

the install fallback path runs:

• `npm run clean-install`
• `npm run install-zstd`
• `bash etc/install-zstd.sh`

Release Highlight

Package can be build from source upon installation

Fixed an issue where installing @mongodb-js/zstd would fail on platforms without a pre-built binary (e.g. new Node.js versions or uncommon architectures). The source-build fallback script etc/install-zstd.sh was not included in the published npm package, causing the installation to exit with bash: etc/install-zstd.sh: No such file or directory. The script is now shipped with the package so that source builds work correctly.
Thanks @axelonet for submitting the fix!

Double check the following

• Lint is passing (`npm run check:lint`)
• Self-review completed using the steps outlined here
• PR title follows the correct format: `type(NODE-xxxx)[!]: description`
  • Example: `feat(NODE-1234)!: rewriting everything in coffeescript`
• Changes are covered by tests
• New TODOs have a related JIRA ticket

[PavelSafronov]

@axelonet , thanks for the PR! The team will look into this fix.

[Copilot]

Pull request overview

Fixes a packaging issue in @mongodb-js/zstd where npm install ... --build-from-source could fail because the install script referenced a file that wasn’t included in the published tarball.

Changes:

• Adds etc/install-zstd.sh to the files allowlist so it is shipped in the npm package.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

You can also share your feedback on Copilot code review. Take the survey.

[tadjik1]

macos jobs stuck due to macos-13 (intel based runners) are deprecated and removed by Github (follow-up https://jira.mongodb.org/browse/NODE-7593)