fix(cli): route os diff's missing-paths usage error to stderr, in both faces - #15875

fix(cli): route os diff's missing-paths usage error to stderr, in both faces#15875

os-litant merged 2 commits into

mainobjectstack-ai/objectstack:mainfrom

claude/issue-15697-diff-usage-error-stderrobjectstack-ai/objectstack:claude/issue-15697-diff-usage-error-stderrCopy head branch name to clipboard