[dev #3] introduction the Boss Reward ver 0.0.5

On Brave Under Coins ver 0.0.5

When you defeat the Boss(Bear)

1. A unique reward lottery is conducted first (25% chance to win, 75% chance to lose).
2. If you fail to win the unique reward, one of the rewards will be selected based on the probability of each rarity shown in the image.
   Note: The game is saved when you press the [Back to Village] button and return to the village.