A support-explicit normal-jet theorem

For the XIV-J interface, $r=3$, $S=S_{\mathrm{resp}}$, and $A=N_U$ in the retained chart. The theorem clarifies the interface but supplies no characteristic coefficients for it Jconditional.

The coverage account distinguishes the codimension-five response incidence, the codimension-eight characteristic locus, and the relative codimension-three flag. Those labels are recorded as source bookkeeping, not independently derived dimensions. They do not replace the extension problem on $N_U$.