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/dom/dist/get-user-code-frame.js

@@ -0,0 +1,55 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.getUserCodeFrame = getUserCodeFrame;
+// We try to load node dependencies
+let chalk = null;
+let readFileSync = null;
+let codeFrameColumns = null;
+try {
+  const nodeRequire = module && module.require;
+  readFileSync = nodeRequire.call(module, 'fs').readFileSync;
+  codeFrameColumns = nodeRequire.call(module, '@babel/code-frame').codeFrameColumns;
+  chalk = nodeRequire.call(module, 'chalk');
+} catch {
+  // We're in a browser environment
+}
+
+// frame has the form "at myMethod (location/to/my/file.js:10:2)"
+function getCodeFrame(frame) {
+  const locationStart = frame.indexOf('(') + 1;
+  const locationEnd = frame.indexOf(')');
+  const frameLocation = frame.slice(locationStart, locationEnd);
+  const frameLocationElements = frameLocation.split(':');
+  const [filename, line, column] = [frameLocationElements[0], parseInt(frameLocationElements[1], 10), parseInt(frameLocationElements[2], 10)];
+  let rawFileContents = '';
+  try {
+    rawFileContents = readFileSync(filename, 'utf-8');
+  } catch {
+    return '';
+  }
+  const codeFrame = codeFrameColumns(rawFileContents, {
+    start: {
+      line,
+      column
+    }
+  }, {
+    highlightCode: true,
+    linesBelow: 0
+  });
+  return `${chalk.dim(frameLocation)}\n${codeFrame}\n`;
+}
+function getUserCodeFrame() {
+  // If we couldn't load dependencies, we can't generate the user trace
+  /* istanbul ignore next */
+  if (!readFileSync || !codeFrameColumns) {
+    return '';
+  }
+  const err = new Error();
+  const firstClientCodeFrame = err.stack.split('\n').slice(1) // Remove first line which has the form "Error: TypeError"
+  .find(frame => !frame.includes('node_modules/')); // Ignore frames from 3rd party libraries
+
+  return getCodeFrame(firstClientCodeFrame);
+}