Prescription and the D11 matching note

Builder/output: prescription_d11.py, P14_prescription_D11_matching.json.

One prescription. Dimensional reduction (DRED), made operational in p14r (Section sec:p14r-dred). Subtraction is $\overline{\mathrm{MS}}$ at scale $\mu$, and the $i0$ is Feynman. The rules for scaleless integrals belong to the definition but are not applied: no tadpole (D02, D12, D14a–c) receives a value. D12 stays Missing. XVI-O fixed D12 and the one-point function by dimensional_regularization_m0; P's prescription belongs to the same family, but P does not import that value.