- Reimplement the GPU cycle heuristics for MersenneNumberIncrementalGpuTester and re-enable Scan_handles_various_prime_exponents once the device path is fixed.
- Extend the GPU numeric type probe to cover proposed custom types such as GpuUInt256 and GpuUInt512 once their definitions are available so we can plan the wide-order heuristics on the device.