fix(core-schemas): use z.custom() with validator for function types in Zod v4#5173

marius-kilocode merged 2 commits intoKilo-Org:mainKilo-Org/kilocode:mainfrom

PeterDaveHelloKitchen:fix/core-schemas-zod-function-apiPeterDaveHelloKitchen/kilocode:fix/core-schemas-zod-function-apiCopy head branch name to clipboard