docs: add warning against npm update -g for global upgrades#55857

SanskaarUndale21 wants to merge 1 commit intoanthropics:mainanthropics/claude-code:mainfrom

SanskaarUndale21:docs/warn-against-npm-update-globalSanskaarUndale21/claude-code:docs/warn-against-npm-update-globalCopy head branch name to clipboard