Navigate an Estate root for cross-file OCL in the model-driven implementation #338

Parent

#324

What

In emf/, add an Estate root that contains every document of a set, and move every cross-file invariant onto it so it navigates containment rather than calling allInstances() (emf 0098). Read a set once, and remove the read-alone-first pass. The refused fixtures' diagnostics must stay byte-identical before and after.

This is a Java-side decision, so it lands inside emf/ alone.

Done when

./mvnw -B -ntp verify in emf/ is green, no .ocl file calls allInstances(), and emf/docs/architecture.md loses its "until #324" paragraph.