Add checked query composition foundations for prepared presentations

Move React navigation query generation behind an explicit build frontend. Add checked result-dependent query bindings and pure composition evaluation, including one-snapshot server execution. Preserve the existing rendering path while the React manifest, worker preparation, and replica admission integration remain pending; see docs/PREPARED_PRESENTATIONS_PROGRESS.md.

src/query/schema.ts

@@ -197,7 +197,12 @@ export function querySchema(
         const metadata = new GraphQLObjectType({
           name: `QxMetadata_${name(id)}`,
           fields: {
-            ...(id === workspaceQueryRootId ? {} : { ref: { type: new GraphQLNonNull(relational.refs(id)) } }),
+            ...(id === workspaceQueryRootId
+              ? {}
+              : {
+                  ref: { type: new GraphQLNonNull(relational.refs(id)) },
+                  atom: { type: new GraphQLNonNull(GraphQLString) },
+                }),
             ...(helpers ? { relations: { type: new GraphQLNonNull(helpers) } } : {}),
           },
         });