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/queries/placeholder-text.js

@@ -0,0 +1,22 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.queryByPlaceholderText = exports.queryAllByPlaceholderText = exports.getByPlaceholderText = exports.getAllByPlaceholderText = exports.findByPlaceholderText = exports.findAllByPlaceholderText = void 0;
+var _queryHelpers = require("../query-helpers");
+var _helpers = require("../helpers");
+var _allUtils = require("./all-utils");
+const queryAllByPlaceholderText = (...args) => {
+  (0, _helpers.checkContainerType)(args[0]);
+  return (0, _allUtils.queryAllByAttribute)('placeholder', ...args);
+};
+const getMultipleError = (c, text) => `Found multiple elements with the placeholder text of: ${text}`;
+const getMissingError = (c, text) => `Unable to find an element with the placeholder text of: ${text}`;
+const queryAllByPlaceholderTextWithSuggestions = exports.queryAllByPlaceholderText = (0, _queryHelpers.wrapAllByQueryWithSuggestion)(queryAllByPlaceholderText, queryAllByPlaceholderText.name, 'queryAll');
+const [queryByPlaceholderText, getAllByPlaceholderText, getByPlaceholderText, findAllByPlaceholderText, findByPlaceholderText] = (0, _allUtils.buildQueries)(queryAllByPlaceholderText, getMultipleError, getMissingError);
+exports.findByPlaceholderText = findByPlaceholderText;
+exports.findAllByPlaceholderText = findAllByPlaceholderText;
+exports.getByPlaceholderText = getByPlaceholderText;
+exports.getAllByPlaceholderText = getAllByPlaceholderText;
+exports.queryByPlaceholderText = queryByPlaceholderText;