Fix CI: update vdiffr snapshots, fix Rd docs, add Copilot setup#45

Copilot wants to merge 4 commits into

mainMerck/gMCPLite:mainfrom

copilot/replace-geom-line-with-geom-curveMerck/gMCPLite:copilot/replace-geom-line-with-geom-curveCopy head branch name to clipboard