Add checked workspace-interface query roots

Implement scoped interface extents across QX, generated bindings, SDK,
Orch, Camino and browser queries. Preserve native projection, aggregation,
pagination and watch invalidation without synthetic persisted objects.
Validate exact query grants and scope freshness on execution and replay.
Add local PostgreSQL, transport, browser and code-generation coverage.

C1 implementation slice only: full-text indexes and Studio search adoption
(C2/C3) remain tracked in the implementation handoff. No publication or deployment.

test/fixtures/query-workspace.ts

@@ -44,6 +44,9 @@ export async function queryWorkspaceFixture(options: { live?: boolean } = {}) {
       operation titleSet id "title-set" : string -> unit mode call receiver any
         requires {state title id "title-port" : string [write];};
       operation score id "score" : unit -> int32 mode call receiver any;
+      query Extent id "extent" root workspace TaskFacts document "extent.graphql" operation "Extent" {
+        max rows 30; watch;
+      }
       query Upcoming id "upcoming" root Collection<interface TaskFacts> document "upcoming.graphql" operation "Upcoming" {
         fragments "row.graphql"; max rows 30; watch;
       }
@@ -73,6 +76,7 @@ export async function queryWorkspaceFixture(options: { live?: boolean } = {}) {
   const pkg: PackageRevision = pkgResult.resource.revision;
   const allInterfaces = [...interfaces.values(), ...(pkgResult.resource.specializations ?? [])];
   const documents: Record<string, string> = {
+    "extent.graphql": `query Extent {root {objects(first: 30, orderBy: [{rank: ASC}]) {entries {node {_qx {ref} title rank}}}}}`,
     "upcoming.graphql": `query Upcoming($first: Int!, $after: Cursor) {root {items(first: $first, after: $after, where: {done: {eq: false}}, orderBy: [{rank: ASC}]) {entries {key cursor node {_qx {ref} ...TaskRow}} pageInfo {hasNextPage endCursor}}}}`,
     "row.graphql": `fragment TaskRow on TaskFacts {title rank done assignee {name}}`,
     "enriched.graphql": `query Enriched {root {items(first: 3) {entries {key node {_qx {ref} title score}}}}}`,