Projects a Member to the template-side value type it contributes to Prototype.
Routes Id and Type markers to Reference and ranged entries to
their range's template model, which already carries cardinality-driven optionality and the scalar-versus-tuple
distinction. Feeds both Prototype assembly (where the projection supplies the value type of the resource's
model, relaxed to an optional key when it admits absence) and Override assignability (where the inherited
side is expanded via Narrowings so the new union-narrowing inheritance forms are accepted).
Projects a Member to the template-side value type it contributes to Prototype.
Routes Id and Type markers to Reference and ranged entries to their range's template model, which already carries cardinality-driven optionality and the scalar-versus-tuple distinction. Feeds both Prototype assembly (where the projection supplies the value type of the resource's
model, relaxed to an optional key when it admits absence) and Override assignability (where the inherited side is expanded via Narrowings so the new union-narrowing inheritance forms are accepted).