Event germs, guard, transport, and finite code

Let ${\mathcal{Q}}_{-}$ be the regular incoming family for $-1\le s<0$, and ${\mathcal{Q}}_{+}$ the outgoing family for $0<s\le 1$. Their certified event germs are ${\mathcal{Q}}_0^{-},{\mathcal{Q}}_0^{+}$. Both realize the same capped surface at $s=0$.

An incoming germ retains the collapsed $EW$ slot and its coincident endpoint labels. The outgoing germ retains the born $NS$ slot and outgoing endpoint metadata. These descriptions have the common four-face junction as their geometric quotient.

The semantic event rule is

It changes mode, permission, and central incidence, but does not advance $s$. Continuous within-epoch evolution is a separate operation.