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/v8-to-istanbul/lib/branch.js

@@ -0,0 +1,28 @@
+module.exports = class CovBranch {
+  constructor (startLine, startCol, endLine, endCol, count) {
+    this.startLine = startLine
+    this.startCol = startCol
+    this.endLine = endLine
+    this.endCol = endCol
+    this.count = count
+  }
+
+  toIstanbul () {
+    const location = {
+      start: {
+        line: this.startLine,
+        column: this.startCol
+      },
+      end: {
+        line: this.endLine,
+        column: this.endCol
+      }
+    }
+    return {
+      type: 'branch',
+      line: this.startLine,
+      loc: location,
+      locations: [Object.assign({}, location)]
+    }
+  }
+}