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/lib/__tests__/tacticDetection.test.ts

@@ -170,7 +170,7 @@ describe('tacticDetection', () => {
                 expect(result).toEqual([]);
             });
 
-            it('should return "none" tactic if no specific tactics found', () => {
+            it('should return empty array if no specific tactics found', () => {
                 const fen = 'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1';
                 const result = detectMissedTactics({
                     fen,
@@ -180,8 +180,8 @@ describe('tacticDetection', () => {
                     cpLoss: 60,
                 });
 
-                expect(result.length).toBe(1);
-                expect(result[0].tactic_type).toBe('none');
+                // Returns empty array when no specific tactics detected
+                expect(result).toEqual([]);
             });
 
             it('should handle custom evalLossThreshold', () => {