test: restore plugin contract testkit imports

src/plugins/contracts/loader.contract.test.ts

@@ -1,4 +1,5 @@
 import { beforeAll, beforeEach, describe, expect, it, vi } from "vitest";
+import { uniqueSortedStrings } from "../../../test/helpers/plugins/contracts-testkit.js";
 import { withBundledPluginAllowlistCompat } from "../bundled-compat.js";
 import {
   loadPluginManifestRegistry,
@@ -7,7 +8,6 @@ import {
 import { __testing as providerTesting } from "../providers.js";
 import { resolvePluginWebSearchProviders } from "../web-search-providers.runtime.js";
 import { providerContractCompatPluginIds } from "./registry.js";
-import { uniqueSortedStrings } from "./testkit.js";
 
 function resolveBundledManifestProviderPluginIds() {
   return uniqueSortedStrings(

src/plugins/contracts/memory-embedding-provider.contract.test.ts

@@ -1,6 +1,9 @@
 import { describe, expect, it } from "vitest";
+import {
+  createPluginRegistryFixture,
+  registerVirtualTestPlugin,
+} from "../../../test/helpers/plugins/contracts-testkit.js";
 import { getRegisteredMemoryEmbeddingProvider } from "../memory-embedding-providers.js";
-import { createPluginRegistryFixture, registerVirtualTestPlugin } from "./testkit.js";
 
 describe("memory embedding provider registration", () => {
   it("rejects non-memory plugins that did not declare the capability contract", () => {

src/plugins/contracts/registry.contract.test.ts

@@ -1,4 +1,5 @@
 import { describe, expect, it } from "vitest";
+import { uniqueSortedStrings } from "../../../test/helpers/plugins/contracts-testkit.js";
 import {
   loadPluginManifestRegistry,
   resolveManifestContractPluginIds,
@@ -16,7 +17,6 @@ import {
   speechProviderContractRegistry,
   webFetchProviderContractRegistry,
 } from "./registry.js";
-import { uniqueSortedStrings } from "./testkit.js";
 
 const REGISTRY_CONTRACT_TIMEOUT_MS = 300_000;
 

src/plugins/contracts/runtime-import-side-effects.contract.test.ts

@@ -1,5 +1,5 @@
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
-import { assertNoImportTimeSideEffects } from "./testkit.js";
+import { assertNoImportTimeSideEffects } from "../../../test/helpers/plugins/contracts-testkit.js";
 
 const listChannelPlugins = vi.hoisted(() =>
   vi.fn(() => [

src/plugins/contracts/shape.contract.test.ts

@@ -1,6 +1,9 @@
 import { describe, expect, it } from "vitest";
+import {
+  createPluginRegistryFixture,
+  registerVirtualTestPlugin,
+} from "../../../test/helpers/plugins/contracts-testkit.js";
 import { buildAllPluginInspectReports } from "../status.js";
-import { createPluginRegistryFixture, registerVirtualTestPlugin } from "./testkit.js";
 
 describe("plugin shape compatibility matrix", () => {
   it("keeps legacy hook-only, plain capability, and hybrid capability shapes explicit", () => {