test(cli): fix act() warnings and add global cleanup

packages/cli/test-setup.ts

@@ -8,6 +8,7 @@ import { vi, beforeEach, afterEach } from 'vitest';
 import { format } from 'node:util';
 import { coreEvents } from '@google/gemini-cli-core';
 import { themeManager } from './src/ui/themes/theme-manager.js';
+import { cleanup } from './src/test-utils/render.js';
 
 // Unset CI environment variable so that ink renders dynamically as it does in a real terminal
 if (process.env.CI !== undefined) {
@@ -79,6 +80,7 @@ beforeEach(() => {
 });
 
 afterEach(() => {
+  cleanup();
   consoleErrorSpy.mockRestore();
 
   vi.unstubAllEnvs();