[Feature] Support Zod on zCustom functions

[dccarmo]

Currently all Zod custom function creators require Convex values properties, which feels weird if you're using Zod for everything.

See:

• https://github.com/get-convex/convex-helpers/blob/main/packages/convex-helpers/server/zod4.ts#L102
• https://github.com/get-convex/convex-helpers/blob/main/packages/convex-helpers/server/zod4.ts#L184
• https://github.com/get-convex/convex-helpers/blob/main/packages/convex-helpers/server/zod4.ts#L266

[ianmacartney]

Yeah I could imagine a ZCustomization that transforms the zod types to the Customization type, and having a zCustomization({ args: { ...zod args }, input }) => { args: {...convex args}, input } that you could use internally.
Or extend the zCustomFunction APIs to allow for either to be passed

[ianmacartney]

For now, you can do zodToConvex for args and parse in the handler