test(ci): stop failing fast

[rrama]

Description

Keep running all tests even if one OS fails.

Checklist

• Read and understood the Code of Conduct and Contributing Guidelines.
• Tests added and all succeed
• N/A
• Linted
• N/A
• CHANGELOG.md updated
• N/A
• README.md updated, if user-facing
• N/A

Screenshots / GIFs

N/A

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scanner	Critical	High	Medium	Low	Total (0)
✅	Licenses	0	0	0	0	0 issues
✅	Code Security	0	0	0	0	0 issues
✅	Open Source Security	0	0	0	0	0 issues

💻 Catch issues earlier using the plugins for VS Code, JetBrains IDEs, Visual Studio, and Eclipse.

[bastiandoetsch]

Single-line CI matrix toggle: fail-fast: false is correctly placed under strategy (sibling of matrix), so all three OS jobs (ubuntu/macos/windows) run to completion instead of being cancelled when one fails — exactly the intent, and useful for seeing cross-platform failures together. No build/test logic affected. Correct.

— AI review