fix(phase1.4): check level-up threshold BEFORE incrementing food counter

- Calculate willLevelUp BEFORE foodsEatenRef.current += 1
- This way the 2nd food that triggers level up is still worth 1 point
- Only AFTER eating it do we level up to 2
- Correct: eat food1(+1)=1pt, eat food2(+1, then lvlup)=2pts, eat food3(+2)=4pts
- Issue was checking >= threshold AFTER incrementing, causing wrong level calculation

src/useGameStatus/useGameStatus.ts

@@ -87,14 +87,17 @@ export function useGameStatus(
              foodManagerRef.current.removeFood(head);
              shouldGrow = true;
 
+             // Check BEFORE incrementing if we're about to level up
+             const willLevelUp = (foodsEatenRef.current + 1) >= FOODS_PER_LEVEL;
+
              foodsEatenRef.current += 1;
 
              setScore((prev) => {
-              // Add points at CURRENT level first
+               // Add points at CURRENT level
                let newScore = prev + levelRef.current;
                
-              // THEN check if we should level up for NEXT food
-              if (foodsEatenRef.current >= FOODS_PER_LEVEL) {
+               // Level up AFTER this food if threshold was reached
+               if (willLevelUp) {
                  const newLevel = levelRef.current + 1;
                  levelRef.current = newLevel;
                  setLevel(newLevel);