Sync v8.1.40: full jax.jit coverage for dense_evolution.mitigation

Sync v8.1.39: jax.jit-compatible project_to_physical/uhlmann_fidelity

Sync v8.1.38 final: polynomial_extrapolate, fixed-budget robustness gain

Sync v8.1.39: correct phaseflip/amplitude_damping finding (was Monte Carlo undersampling)

Sync v8.1.38: broader qubit/noise-type sweep for density-matrix ZNE healing

Sync v8.1.37: density-matrix ZNE healing

Sync dense_evolution/ from v8.1.33