refactor: separate score calculation from score management

BREAKING CHANGES:
- Remove timeLimit from GameOptions (use gameOver function instead)
- Remove finalScore from ScoreManager (pure data collection only)
- Remove rows/cols parameters from useScore
- Remove finalScore calculation logic from useScore hook

ADDITIONS:
- Create calculateMazeScore() utility function
- ScoreManager now only returns raw metrics: timeValue, keystrokes, optimalSteps, efficiency, distToKey, distToExit
- Score calculation moved to consumer (calculateMazeScore takes scoreManager + mazeSize)
- Example app now uses calculateMazeScore to compute final score on game-won

BENEFITS:
- ScoreManager is now a pure data collector with no side effects
- Scoring algorithm is reusable and testable in isolation
- Game-over conditions fully controlled via gameOver option
- Clear separation of concerns: collection vs calculation

src/useGame.ts

@@ -6,7 +6,7 @@ import { useHeroRender } from './useCursor';
 import { useScore } from './useScore';
 
 export function useGame(options: GameOptions, platformHook?: unknown): GameManager {
-  const { cols, rows, timeLimit = 600, gameOver } = options;
+  const { cols, rows, gameOver } = options;
   const board = useBoard(cols, rows);
   const { containerRef, renderBoard } = board;
   const gameStatusManager = useGameStatus();
@@ -14,7 +14,7 @@ export function useGame(options: GameOptions, platformHook?: unknown): GameManag
   
   const hero = cursor.hero;
   const renderer = useHeroRender({ gameStatus: gameStatusManager.gameStatus, board, hero });
-  const scoreManager = useScore({ board, hero, gameStatusManager, keyManager, rows, cols, timeLimit, gameOver });
+  const scoreManager = useScore({ board, hero, gameStatusManager, keyManager, gameOver });
 
   const gameManager: GameManager = {
     containerRef,