feat: implement game-over logic with time and hint limits

- Add configurable timeLimit to GameOptions (default 600 seconds / 10 minutes)
- Time limit applies to all difficulty levels (harder puzzles = more time pressure)
- Implement game-over triggers:
  1. Time limit exceeded: timeValue >= timeLimit → 'Time's up!'
  2. Hint penalty limit: hintsUsed * penalty >= 500 → 'Too many hints!'
- Hint limits by difficulty:
  - Easy: 20 hints max (20 × 25 = 500 points)
  - Medium: 10 hints max (10 × 50 = 500 points)
  - Hard: 5 hints max (5 × 100 = 500 points)
- Add gameOverReason to ScoreManager to display specific failure reason
- Timer stops on game-over
- Update example app to show game-over reason
- Both conditions checked during gameplay before win condition

src/useGame.ts

@@ -7,7 +7,7 @@ import { useCursorRender } from './useCursor/useCursorRender';
 import { useScore } from './useScore';
 
 export function useGame(options: GameOptions = {}, platformHook?: unknown): GameManager {
-  const { difficulty = 'easy' } = options;
+  const { difficulty = 'easy', timeLimit = 600 } = options;
   const board = useBoard();
   const { containerRef, renderBoard, generateBoard, boardRendered } = board;
   
@@ -24,7 +24,7 @@ export function useGame(options: GameOptions = {}, platformHook?: unknown): Game
   const cursorPosition = cursor.position();
   const cursorMode = cursor.mode();
   
-  const scoreManager = useScore({ board, gameStatusManager, keyLog, cursorMode, difficulty, hintsUsed: hintsUsedRef.current });
+  const scoreManager = useScore({ board, gameStatusManager, keyLog, cursorMode, difficulty, hintsUsed: hintsUsedRef.current, timeLimit });
   
   useCursorRender(containerRef, cursorPosition, cursorMode, gameStatus, boardRendered);