Development Task

TiKV need support a dedicated RPC endpoint for versioned lookup:

• tikvpb.VersionedKv.VersionedCoprocessor(coprocessor.Request) -> coprocessor.Response

versioned_ranges requests must use this new endpoint.
The legacy coprocessor APIs (Tikv.Coprocessor / stream / batch coprocessor path) explicitly reject requests carrying versioned_ranges.

This task is to add TiCI-side support for sending versioned coprocessor requests through the new VersionedKv service.