test: restore task 2 review coverage

backend/test/workspace-registry.test.ts

@@ -139,6 +139,18 @@ function legacyV1Yaml(source = validYaml): string {
     .replace("schema_version: 3", "schema_version: 1");
 }
 
+function legacyV2Yaml(source = validYaml): string {
+  return source
+    .replace("    engine: qdrant\n", "    engine: pgvector\n    database: postgres\n    schema: vectors\n")
+    .replace("    collection: psd-clinical\n", "    collection: psd_clinical\n")
+    .replace("    dimensions: 1024", "    dimensions: 768")
+    .replace("    provider: ollama_internal", "    provider: ollama_compatible")
+    .replace("    model: qwen3-embedding:0.6b", "    model: nomic-embed-text-v2-moe")
+    .replace("    dimensions: 1024", "    dimensions: 768")
+    .replace("distance: cosine\n", "distance: cosine\n    supported_transports: [pgvector_direct]\n")
+    .replace("schema_version: 3", "schema_version: 2");
+}
+
 const runFile = promisify(execFile);
 const temporaryRoots: string[] = [];
 
@@ -639,6 +651,19 @@ test("does not acquire a session revision lease for a migration_required workspa
   });
 });
 
+test("lists a schema v2 descriptor as migration_required and refuses to acquire it", async () => {
+  const remote = await fixture(legacyV2Yaml());
+  const registry = new WorkspaceRegistry(config(join(remote.root, "registry"), remote.remote));
+  await registry.bootstrap();
+
+  await expect(registry.list()).resolves.toMatchObject([
+    { id: "psd-clinical", state: "migration_required" },
+  ]);
+  await expect(registry.acquireSessionRevision("psd-clinical")).rejects.toMatchObject({
+    code: "workspace_invalid",
+  });
+});
+
 test("lists operational descriptors retained after their workspace was removed from the active revision", async () => {
   const remote = await fixture();
   const root = join(remote.root, "registry");