fix: add zod/v4 fallback for toJSONSchema detection (fixes #1845)#1918

kagura-agent wants to merge 3 commits intobrowserbase:mainbrowserbase/stagehand:mainfrom

kagura-agent:fix/zod-v4-schema-detectionkagura-agent/stagehand:fix/zod-v4-schema-detectionCopy head branch name to clipboard