Implement implicit object references and capability query foundations

src/execution-world/query-operators.ts

@@ -10,6 +10,7 @@ export function unsupportedQueryOperator(query: CheckedQuery): string | undefine
     if (value.kind === "reduce") return "aggregate predicates";
     if (value.kind === "and" || value.kind === "or") return value.children.map(predicate).find(Boolean);
     if (value.kind === "not") return predicate(value.child);
+    if (value.kind === "as") return predicate(value.predicate);
     if (value.kind === "compare") return path(value.expression.path);
     if (value.kind === "relation") return path(value.path) ?? (value.predicate && predicate(value.predicate));
     return undefined;