Function compile_epistemic_gpu_execution 

pub fn compile_epistemic_gpu_execution(
    program: &Program,
) -> Result<EpistemicExecutablePlan>

Compile an epistemic program into its GPU contract and reduced runtime plan.

This is the first production-lowering boundary for epistemic execution. It removes epistemic literals only after plan_epistemic_gpu_execution proves the explicit EIR/GPU semantic contract, then sends the ordinary reduced program through the same compiler, optimizer, helper-splitting, and WCOJ promotion pipeline used by non-epistemic programs.