feat!: retirer readUnion de la surface publiee, et lire un document par requete ancree

readUnion etait N requetes ancrees plus une politique de lot : une lecture
qui echoue avalee en reponse vide, un document dont on ne detient pas la cle
ecarte au lieu d'etre refuse, un regroupement en sacs de proprietes, et le
filtrage du prefixe reserve. Rien en amont ne repond a cette composition, et
son annotation citait sparql_query -- une citation exacte attachee a une
affirmation fausse. Une composition ne s'aligne pas sur une fonction.

Ce qui reste est ce qu'il y avait dessous : docs.sparqlQuery ancre sur un
document, qui va deja chercher la cle servie par le magasin public -- donc
une reference nue suffit toujours pour lire un document public, sans rien
changer a useShapeQuery. Lire plusieurs documents, c'est cet appel une fois
par document, et la tolerance a une lecture qui echoue revient a l'appelant,
la ou l'amont la laisse : une requete ancree sur un depot que le verifier ne
detient pas rejette.

Cote src, l'unique lecture interne restante devient read-document.ts : un
document, une requete ancree, precedee de l'ouverture du depot -- barriere
que index-deposit consulte pour distinguer une absence d'un depot non
synchronise. Le harnais e2e et l'exemple composent la leur, avec leur catch
visible au point d'appel.

Version majeure : 1.0.0-dev.8.

packages/polyfill/test/open-repo.test.ts

@@ -13,13 +13,16 @@
  *   - doc_subscribe is a mock that records calls, fires the callback once
  *     (simulating the initial State push), then returns an unsubscribe fn.
  *
- * We test ensureRepoOpen via readUnion (from read-model) because that is the
- * production caller — it gates on ensureReposOpen internally.
+ * We test ensureRepoOpen via `readDocumentSubjects` (from `surface/read-document`)
+ * because that is the production caller — it opens the document before its anchored
+ * read, and `emulated-verifier/index-deposit.ts` depends on that ordering to tell an
+ * absence from an unsynced repo. It was `readUnion` until `1.0.0-dev.8`; the integration
+ * path is the same one, minus the batch.
  */
 
 import { describe, it, expect, mock, beforeEach, afterAll } from "bun:test";
 import { ensureRepoOpen, ensureReposOpen, resetOpenedRepos } from "../src/emulated-verifier/open-repo";
-import { readUnion } from "../src/surface/read-model";
+import { readDocumentSubjects } from "../src/surface/read-document";
 import { configure } from "../src/index";
 import { configureStoreRegistry, setCurrentUser } from "../src/shared-wallet/bootstrap";
 import { resetCaps, resetConfig, resetStoreRegistry } from "../src/shared-wallet/bootstrap";
@@ -115,7 +118,7 @@ describe("ensureRepoOpen", () => {
     expect(ng.subscribeCallOrder[0]).toBe("did:ng:o:a");
 
     // sparql_query was called AFTER subscribe (ensureRepoOpen guarantees ordering)
-    const result = await readUnion(["did:ng:o:a"]);
+    const result = await readDocumentSubjects("did:ng:o:a");
     expect(result.length).toBe(1);
     expect(result[0]!.props[`${FP}title`]).toEqual(["Alpha"]);
   });
@@ -127,7 +130,7 @@ describe("ensureRepoOpen", () => {
     inject(ng);
 
     // Do NOT call ensureRepoOpen — subscribed Set remains empty
-    // Query directly (bypass readUnion which calls ensureReposOpen internally)
+    // Query directly (bypass `readDocumentSubjects`, which opens the repo internally)
     const result = await ng.sparql_query("sid-or", "SELECT ?s ?p ?o WHERE { ?s ?p ?o }", undefined, "did:ng:o:a");
     const bindings = (result as any).results.bindings;
     expect(bindings.length).toBe(0); // not subscribed → 0 rows (confirms fake design)
@@ -203,15 +206,15 @@ describe("ensureReposOpen", () => {
     expect(ng.doc_subscribe).toHaveBeenCalledTimes(0);
   });
 
-  it("readUnion triggers doc_subscribe then returns data (integration path)", async () => {
+  it("the anchored document read triggers doc_subscribe then returns data (integration path)", async () => {
     const ng = makeFakeNgWithSubscribe({
       "did:ng:o:p": [[TYPE, `${FP}Participation`], [`${FP}event`, "did:ng:o:e"]],
     });
     inject(ng);
 
-    const subjects = await readUnion(["did:ng:o:p"]);
+    const subjects = await readDocumentSubjects("did:ng:o:p");
 
-    // doc_subscribe was called as part of ensureReposOpen inside readUnion
+    // doc_subscribe was called as part of the `ensureRepoOpen` inside the read
     expect(ng.doc_subscribe).toHaveBeenCalledTimes(1);
     expect(subjects.length).toBe(1);
     expect(subjects[0]!.props[`${FP}event`]).toEqual(["did:ng:o:e"]);