This PR updates `CONTRIBUTING.md` for clarity (code review, maintainers,
PR workflow)
## Suggestion
- majors about every **three months**, with a more predictable cadence
from **v1.26** onward.
- target dates such as **v1.26.0** (April 2026), **v1.27.0** (June
2026), **v1.28.0** (September 2026), **v1.29.0** (December 2026).
- announce feature freeze **two weeks** before each release.
## Other doc changes
- Reviewing PRs: separate guidance for reviewers vs authors; small edits
to maintaining PRs, merge queue, commit messages, co-authors.
- Maintainers: clearer subsections; links to GitHub Docs for 2FA / GPG.
- Split the Contributing.md into more useful markdown files
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Signed-off-by: Nicolas <bircni@icloud.com>
