Update ScoreboardManager.java

[cp12r]

**Improved Readability:**
    Used meaningful method names and added comments to clarify the purpose of each method.

**New Methods:**
    updateScoreboardWithShopInfo(Player player, int shards): Updates the player's scoreboard with their current shard count.
    refreshAllScoreboards(): Refreshes the scoreboard for all players in the game.
    refreshSidebarForPlayer(Player player): Refreshes the sidebar for a specific player.

**Shop Information Handling:**
    The updateScoreboardWithShopInfo method allows for easy integration of shop-related data into the player's scoreboard.

Usage:

Call updateScoreboardWithShopInfo(player, shards) whenever a player buys an item from the shop to update their scoreboard with the new shard count.
Use refreshAllScoreboards() to refresh all players' scoreboards, for example, after a game reset or when a significant event occurs.