Set up comprehensive frontend testing infrastructure

- Install Jest for unit testing with React Testing Library
- Install Playwright for end-to-end testing
- Configure Jest with proper TypeScript support and module mapping
- Create test setup files and utilities for both unit and e2e tests

Components:
* Jest configuration with coverage thresholds
* Playwright configuration with browser automation
* Unit tests for LoginForm, AuthContext, and useSocketIO hook
* E2E tests for authentication, dashboard, and agents workflows
* GitHub Actions workflow for automated testing
* Mock data and API utilities for consistent testing
* Test documentation with best practices

Testing features:
- Unit tests with 70% coverage threshold
- E2E tests with API mocking and user journey testing
- CI/CD integration for automated test runs
- Cross-browser testing support with Playwright
- Authentication system testing end-to-end

🚀 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/node_modules/@testing-library/jest-dom/dist/vitest.js

@@ -0,0 +1,16 @@
+'use strict';
+
+var vitest = require('vitest');
+var matchers = require('./matchers-7fb38cd4.js');
+require('redent');
+require('@adobe/css-tools');
+require('dom-accessibility-api');
+require('aria-query');
+require('chalk');
+require('lodash/isEqualWith.js');
+require('css.escape');
+
+/* istanbul ignore file */
+
+
+vitest.expect.extend(matchers.extensions);