refactor(test): share gateway e2e registry helper

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

@@ -10,6 +10,7 @@ import { BARE_SESSION_RESET_PROMPT } from "../auto-reply/reply/session-reset-pro
 import { emitAgentEvent, registerAgentRunContext } from "../infra/agent-events.js";
 import { GATEWAY_CLIENT_MODES, GATEWAY_CLIENT_NAMES } from "../utils/message-channel.js";
 import { setRegistry } from "./server.agent.gateway-server-agent.mocks.js";
+import { createRegistry } from "./server.e2e-registry-helpers.js";
 import {
   agentCommand,
   connectOk,
@@ -42,22 +43,6 @@ afterAll(async () => {
   await server.close();
 });
 
-const _BASE_IMAGE_PNG =
-  "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mP8/x8AAwMCAO+X3mIAAAAASUVORK5CYII=";
-
-const createRegistry = (channels: PluginRegistry["channels"]): PluginRegistry => ({
-  plugins: [],
-  tools: [],
-  channels,
-  providers: [],
-  gatewayHandlers: {},
-  httpHandlers: [],
-  httpRoutes: [],
-  cliRegistrars: [],
-  services: [],
-  diagnostics: [],
-});
-
 const createMSTeamsPlugin = (params?: { aliases?: string[] }): ChannelPlugin => ({
   id: "msteams",
   meta: {