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/w3c-xmlserializer/lib/constants.js

@@ -0,0 +1,44 @@
+"use strict";
+
+module.exports.NAMESPACES = {
+  HTML: "http://www.w3.org/1999/xhtml",
+  XML: "http://www.w3.org/XML/1998/namespace",
+  XMLNS: "http://www.w3.org/2000/xmlns/"
+};
+
+module.exports.NODE_TYPES = {
+  ELEMENT_NODE: 1,
+  ATTRIBUTE_NODE: 2, // historical
+  TEXT_NODE: 3,
+  CDATA_SECTION_NODE: 4,
+  ENTITY_REFERENCE_NODE: 5, // historical
+  ENTITY_NODE: 6, // historical
+  PROCESSING_INSTRUCTION_NODE: 7,
+  COMMENT_NODE: 8,
+  DOCUMENT_NODE: 9,
+  DOCUMENT_TYPE_NODE: 10,
+  DOCUMENT_FRAGMENT_NODE: 11,
+  NOTATION_NODE: 12 // historical
+};
+
+module.exports.VOID_ELEMENTS = new Set([
+  "area",
+  "base",
+  "basefont",
+  "bgsound",
+  "br",
+  "col",
+  "embed",
+  "frame",
+  "hr",
+  "img",
+  "input",
+  "keygen",
+  "link",
+  "menuitem",
+  "meta",
+  "param",
+  "source",
+  "track",
+  "wbr"
+]);