♻️ refactor: player 조회 메서드 추가

Author: LimKangHyun

backend/src/main/java/io/f1/backend/domain/game/app/GameService.java

@@ -78,10 +78,7 @@ public void handlePlayerReady(Long roomId, String sessionId) {
 
         Room room = findRoom(roomId);
 
-        Player player = room.getPlayerSessionMap().get(sessionId);
-        if (player == null) {
-            throw new CustomException(RoomErrorCode.PLAYER_NOT_FOUND);
-        }
+        Player player = room.getPlayerBySessionId(sessionId);
 
         toggleReadyIfPossible(room, player);
 

backend/src/main/java/io/f1/backend/domain/game/model/Room.java

@@ -146,6 +146,14 @@ public boolean validateReadyStatus() {
         return playerSessionMap.values().stream().allMatch(Player::isReady);
     }
 
+    public Player getPlayerBySessionId(String sessionId) {
+        Player player = playerSessionMap.get(sessionId);
+        if (player == null) {
+            throw new CustomException(RoomErrorCode.PLAYER_NOT_FOUND);
+        }
+        return player;
+    }
+
     public void resetAllPlayerReadyStates() {
         for (Player player : playerSessionMap.values()) {
             if (Objects.equals(player.getId(), getHost().getId())) continue;