refactor(test): share gateway e2e registry helper

src/gateway/server.channels.e2e.test.ts

@@ -2,6 +2,7 @@ import { afterAll, beforeAll, describe, expect, test, vi } from "vitest";
 import type { ChannelPlugin } from "../channels/plugins/types.js";
 import type { PluginRegistry } from "../plugins/registry.js";
 import { setActivePluginRegistry } from "../plugins/runtime.js";
+import { createRegistry } from "./server.e2e-registry-helpers.js";
 import {
   connectOk,
   installGatewayTestHooks,
@@ -41,19 +42,6 @@ vi.mock("./server-plugins.js", async () => {
   };
 });
 
-const createRegistry = (channels: PluginRegistry["channels"]): PluginRegistry => ({
-  plugins: [],
-  tools: [],
-  channels,
-  providers: [],
-  gatewayHandlers: {},
-  httpHandlers: [],
-  httpRoutes: [],
-  cliRegistrars: [],
-  services: [],
-  diagnostics: [],
-});
-
 const createStubChannelPlugin = (params: {
   id: ChannelPlugin["id"];
   label: string;