feat(adopters): add Knowledge Commons to adopters with 2025 audit and commitment and 2026 audit

This change adds Knowledge Commons (KC) to the list of POSI adopters.

KC pledged to adopt POSI in May 2025 and published its first audit then. We have just completed our 2026 update audit and realised that KC is not listed among the adopters.

This merge request adds KC in alphabetical order to the adopters list and renumbers all subsequent adopters to keep the sequence in tact.