Sort contributor listings alphabetically by first name

[Copilot]

This PR addresses the requirement to sort contributor listings in README.md alphabetically by first name.

Changes Made

• Approvers section: Reordered entries to sort alphabetically by first name (Anton, Björn, Scott, Shaun)
• Emeritus section: Reordered entries to sort alphabetically by first name (Dirkjan, Isobel, Jan, Julian, Mike)
• Maintainers section: Already correctly sorted, no changes needed

Notes

• CONTRIBUTING.md was checked but contains no specific contributor listings to sort
• All emeritus members already had no company affiliations, so no removal was necessary
• Changes are minimal and surgical - only 2 people reordered across both sections

Fixes #15.

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