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/y18n/build/lib/platform-shims/node.js

@@ -0,0 +1,19 @@
+import { readFileSync, statSync, writeFile } from 'fs';
+import { format } from 'util';
+import { resolve } from 'path';
+export default {
+    fs: {
+        readFileSync,
+        writeFile
+    },
+    format,
+    resolve,
+    exists: (file) => {
+        try {
+            return statSync(file).isFile();
+        }
+        catch (err) {
+            return false;
+        }
+    }
+};