chore(master): release 9.0.0

[github-actions]

🤖 I have created a release beep boop

9.0.0 (2026-09-01)

⚠ BREAKING CHANGES

• Error instances no longer expose .cause() as a callable function. Consumers must access the spec-compliant .cause property instead. Bump @netflix/nerror dependency/override to ^2.0.0 and package version to 9.0.0 accordingly.

Bug Fixes

• ci: move ci to gha (7e053db)
• ci: move node 24 to new optional tests (10564a8)
• include cause in toJSON (f8cb6fb)
• npm publish workflow (#113) (7e94768)
• use spec Error.cause property instead of legacy cause() function (#112) (4a6fb33)

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[github-actions]

🤖 Created releases:

• v9.0.0

🌻