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/data-urls/lib/utils.js

@@ -0,0 +1,20 @@
+"use strict";
+
+exports.stripLeadingAndTrailingASCIIWhitespace = string => {
+  return string.replace(/^[ \t\n\f\r]+/u, "").replace(/[ \t\n\f\r]+$/u, "");
+};
+
+exports.isomorphicDecode = input => {
+  return Array.from(input, byte => String.fromCodePoint(byte)).join("");
+};
+
+exports.forgivingBase64Decode = data => {
+  let asString;
+  try {
+    asString = atob(data);
+  } catch {
+    return null;
+  }
+
+  return Uint8Array.from(asString, c => c.codePointAt(0));
+};