This PR updates the codebase to support the latest version of zod (v4.1.5) while maintaining backwards compatibility with zod v3.21.4+.

Changes Made

Type System Updates

• Replaced ZodEffects with ZodTransform: Updated all type imports and usage to use the new ZodTransform type that replaced ZodEffects in zod v4
• Removed ZodNativeEnum import: This type is no longer exported in zod v4
• Fixed type constraints: Updated WithZodAdditions to properly constrain the generic parameter to string | number | boolean to work with ZodLiteral
• Added WithZodAdditionsDate: Created a separate type helper for Date handling since Date cannot be used with ZodLiteral

Runtime Compatibility

• Updated error handling: Changed from results.error.errors to results.error.issues to match zod v4's new error structure
• Fixed path type casting: Added proper type casting for zod error paths to maintain compatibility with the existing KeyChain type system
• Simplified opts return types: Made the return types for array and object validation options more permissive to handle zod v4's stricter type checking

Package Configuration

• Updated peerDependencies: Changed from "zod": "3.*" to "zod": "^3.21.4 || ^4.0.0" to support both major versions

Testing

All existing tests continue to pass with both zod v3.21.4 and v4.1.5, ensuring the changes maintain full backwards compatibility while enabling users to upgrade to the latest zod version.

Example Usage

The validation API remains unchanged:

const schema: IValidationSchema<FormData> = {
  name: z.string(),
  email: z.string().email(),
  address: {
    schema: {
      street: z.string(),
      city: z.string(),
    },
    opts: ob => ob.required()
  }
};

// Works with both zod v3 and v4
const zodSchema = zodFromValidationSchema(schema);

This update ensures the library stays current with the zod ecosystem while providing a smooth upgrade path for users.

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