feat(phase2.2): implement finalScore calculation

- finalScore equals current game score when gameStatus is 'game-over' or 'game-won'
- finalScore is null during active gameplay ('waiting' and 'started')
- Passed currentScore from gameManager to useScore hook

src/useGame/useGame.ts

@@ -46,7 +46,7 @@ export function useGame(optionsOrCols: GameOptions | number, rows?: number, plat
     },
   });
 
-  const scoreManager = useScore({ gameStatus, keyLog: keyBindings.keyLog });
+  const scoreManager = useScore({ gameStatus, keyLog: keyBindings.keyLog, currentScore: score });
 
   // Wrap renderBoard to match Unified API signature
   const renderBoardWrapped = () => {

src/useScore/useScore.ts

@@ -5,18 +5,21 @@ import type { GameStatus, KeyLogEntry } from "../types";
 export type UseScoreParams = {
   gameStatus: GameStatus;
   keyLog: KeyLogEntry[];
+  currentScore: number;
 };
 
-export function useScore({ gameStatus, keyLog }: UseScoreParams) {
+export function useScore({ gameStatus, keyLog, currentScore }: UseScoreParams) {
   const timer = useTimer();
   const { timeValue, startTimer, stopTimer, resetTimer } = timer;
 
   useScoreTime({ gameStatus, timer });
 
+  const finalScore = gameStatus === 'game-over' || gameStatus === 'game-won' ? currentScore : null;
+
   return {
     timeValue,
     totalKeystrokes: keyLog.length,
-    finalScore: null,   // TODO: Calculate on game-won
+    finalScore,
     startTimer,
     stopTimer,
     resetTimer,