The reportError function signature was missing the WrenVM* parameter required by the updated Wren API, causing a compilation error when the CLI attempted to register it as the error callback. Added the vm parameter to match the expected callback type.
Add a `userData` void pointer field to `WrenConfiguration` and expose `wrenGetUserData`/`wrenSetUserData` functions for associating arbitrary state with a VM instance. Also update the `WrenErrorFn` signature to include the `WrenVM*` parameter, and propagate the VM pointer through all error callback invocations in the compiler, debug, and runtime paths.
scott