Clarify UIK contribution requirements for GitLab team members and community contributors (!5202) · Merge requests · GitLab.org / gitlab-services / Pajamas Design System · GitLab

Relates to issue #3043

This MR was created by Duo in Session 1162769

Changes

Restructure UIK contributing documentation to clearly distinguish between internal GitLab team member contributions and external community contributions
Add warning about Figma organization access requirements for internal contributions
Provide guidance for external contributors on how to share design concepts without direct Figma file access