refactor(test): share gateway server plugin mocks

src/gateway/server.agent.gateway-server-agent.mocks.ts

@@ -0,0 +1,36 @@
+import { vi } from "vitest";
+import type { PluginRegistry } from "../plugins/registry.js";
+import { setActivePluginRegistry } from "../plugins/runtime.js";
+
+export const registryState: { registry: PluginRegistry } = {
+  registry: {
+    plugins: [],
+    tools: [],
+    channels: [],
+    providers: [],
+    gatewayHandlers: {},
+    httpHandlers: [],
+    httpRoutes: [],
+    cliRegistrars: [],
+    services: [],
+    diagnostics: [],
+  } as PluginRegistry,
+};
+
+export function setRegistry(registry: PluginRegistry) {
+  registryState.registry = registry;
+  setActivePluginRegistry(registry);
+}
+
+vi.mock("./server-plugins.js", async () => {
+  const { setActivePluginRegistry } = await import("../plugins/runtime.js");
+  return {
+    loadGatewayPlugins: (params: { baseMethods: string[] }) => {
+      setActivePluginRegistry(registryState.registry);
+      return {
+        pluginRegistry: registryState.registry,
+        gatewayMethods: params.baseMethods ?? [],
+      };
+    },
+  };
+});