Ground

The SEAM (SPLICE-BUILD-SPEC steps 2+3): reduce the question (cached when seen before), digest it, then match every leaf against the endpoint registry with the three-state verdict (executable-now / plannable / blocked; plannable = schema-known route, execution deferred until the connection is authorized — a handoff, not a failure). Returns {digest, grounding} — the route skeleton plus how much of it is live.