refactor: code review improvements

- Add 30s timeout to Stockfish evaluation to prevent hanging promises
- Add FEN validation and depth cap (max 30) to Stockfish API route
- Create ErrorBoundary component with specialized fallbacks for chess game and tutor
- Extract useChessSounds hook for better audio management
- Add React.memo to EvaluationBar and CapturedPieces for performance
- Add useMemo to CapturedPieces for sorted pieces calculation
- Improve tacticDetection to return empty array instead of "none" type
- Add filterMeaningfulTactics and hasTactics helper functions
- Translate hardcoded UI strings (stockfishLevel, download, evalChange)
- Update translations for EN, DE, FR, IT, PL
- Add uuid to Jest transformIgnorePatterns for ESM compatibility
- Update tests to use new filterMeaningfulTactics function

src/contexts/__tests__/OpeningTrainingContext.test.tsx

@@ -10,6 +10,11 @@
  * This is Phase 5 of the refactoring plan - comprehensive testing.
  */
 
+// Mock uuid before any imports
+jest.mock('uuid', () => ({
+  v4: jest.fn(() => 'test-uuid-1234'),
+}));
+
 import React from 'react';
 import { renderHook, act, waitFor } from '@testing-library/react';
 import { OpeningTrainingProvider, useOpeningTraining } from '../OpeningTrainingContext';