refactor(test): share gateway e2e registry helper

src/gateway/server.agent.gateway-server-agent-a.e2e.test.ts

@@ -5,6 +5,7 @@ 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 { setRegistry } from "./server.agent.gateway-server-agent.mocks.js";
+import { createRegistry } from "./server.e2e-registry-helpers.js";
 import {
   agentCommand,
   connectOk,
@@ -42,19 +43,6 @@ function expectChannels(call: Record<string, unknown>, channel: string) {
   expect(runContext?.messageChannel).toBe(channel);
 }
 
-const createRegistry = (channels: PluginRegistry["channels"]): PluginRegistry => ({
-  plugins: [],
-  tools: [],
-  channels,
-  providers: [],
-  gatewayHandlers: {},
-  httpHandlers: [],
-  httpRoutes: [],
-  cliRegistrars: [],
-  services: [],
-  diagnostics: [],
-});
-
 const createStubChannelPlugin = (params: {
   id: ChannelPlugin["id"];
   label: string;