Add comprehensive performance monitoring and testing infrastructure

- Implement performance dashboard with real-time metrics tracking
- Add React hooks for smart polling, debouncing, and active source lookup
- Create Jest testing framework with comprehensive test suites for components, API endpoints, and utilities
- Enhance UI components with optimized rendering and memoization
- Improve polling efficiency with visibility detection and adaptive intervals

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

jest.setup.js

@@ -0,0 +1,69 @@
+import '@testing-library/jest-dom';
+import { TextEncoder, TextDecoder } from 'util';
+
+// Polyfills for Node.js environment
+global.TextEncoder = TextEncoder;
+global.TextDecoder = TextDecoder;
+
+// Mock NextResponse for API route testing  
+jest.mock('next/server', () => ({
+  NextResponse: {
+    json: jest.fn((data, options) => ({
+      data,
+      status: options?.status || 200,
+      json: async () => data,
+    })),
+  },
+}));
+
+// Mock Next.js router
+jest.mock('next/navigation', () => ({
+  useRouter() {
+    return {
+      push: jest.fn(),
+      replace: jest.fn(),
+      prefetch: jest.fn(),
+      back: jest.fn(),
+      forward: jest.fn(),
+      refresh: jest.fn(),
+    };
+  },
+  useParams() {
+    return {};
+  },
+  usePathname() {
+    return '';
+  },
+  useSearchParams() {
+    return new URLSearchParams();
+  },
+}));
+
+// Mock window.confirm for delete operations
+global.confirm = jest.fn(() => true);
+
+// Mock console.error to avoid noise in tests
+const originalError = console.error;
+beforeAll(() => {
+  console.error = (...args) => {
+    if (
+      typeof args[0] === 'string' &&
+      args[0].includes('Warning: ReactDOM.render is no longer supported')
+    ) {
+      return;
+    }
+    originalError.call(console, ...args);
+  };
+});
+
+afterAll(() => {
+  console.error = originalError;
+});
+
+// Mock fetch globally
+global.fetch = jest.fn();
+
+// Reset all mocks between tests
+beforeEach(() => {
+  jest.clearAllMocks();
+});