• Merge pull request #1088 from kaitranntt/kai/feat/design-system-foundations
• fix(ui): address PR-Agent round 3 review on ConfigLayout duplicate DOM
• fix(ui): address PR-Agent round 2 review feedback
• fix(ui): address PR-Agent review feedback on JsonPane and SectionRail
• docs(ui): add design system visual preview + screenshots
• feat(ui): add design system foundations