Add persistent player stats and DB support

Introduce MySQL persistence and an in-memory stats system with async saving.

- Add HikariCP & MySQL connector dependencies and relocate libs in build.gradle.kts.
- Add DatabaseManager (HikariCP) to manage connection pool and lifecycle.
- Add PlayerStats data model and PlayerStatsRepository for table creation, reads, upserts and batch upserts (with prepared statements).
- Add StatsManager: coroutine-based cache, dirty-flags, async batch saves, auto-save (every 5 minutes), load/save APIs and shutdown save.
- Add StatsListener: load on AsyncPlayerPreLoginEvent and save on PlayerQuitEvent.
- Wire DB and stats into main plugin: connect on enable (disable plugin on fail), initialize StatsManager, save/disconnect on disable, register leaderboard command and stats listener.
- Update GameManager to record kills/wins/deaths and adjust scrimScore on events.
- Add LeaderboardCommand and language entries for leaderboard output; expose command in plugin.yml.
- Add database configuration section to config.yml.
- Minor refactor: KitCommand plugin accessor changed to a getter.

These changes provide a robust, pooled DB connection and efficient stats persistence (batched/upserted) to reduce DB load and ensure data safety during shutdown.

src/main/kotlin/club/mcscrims/speedhg/SpeedHG.kt

@@ -1,7 +1,10 @@
 package club.mcscrims.speedhg
 
 import club.mcscrims.speedhg.command.KitCommand
+import club.mcscrims.speedhg.command.LeaderboardCommand
 import club.mcscrims.speedhg.config.LanguageManager
+import club.mcscrims.speedhg.database.DatabaseManager
+import club.mcscrims.speedhg.database.StatsManager
 import club.mcscrims.speedhg.game.GameManager
 import club.mcscrims.speedhg.game.modules.AntiRunningManager
 import club.mcscrims.speedhg.kit.KitManager
@@ -13,6 +16,7 @@ import club.mcscrims.speedhg.kit.listener.KitEventDispatcher
 import club.mcscrims.speedhg.listener.ConnectListener
 import club.mcscrims.speedhg.listener.GameStateListener
 import club.mcscrims.speedhg.listener.SoupListener
+import club.mcscrims.speedhg.listener.StatsListener
 import club.mcscrims.speedhg.scoreboard.ScoreboardManager
 import org.bukkit.Bukkit
 import org.bukkit.plugin.java.JavaPlugin
@@ -41,21 +45,37 @@ class SpeedHG : JavaPlugin() {
 	lateinit var kitManager: KitManager
 		private set
 
+	lateinit var databaseManager: DatabaseManager
+		private set
+
+	lateinit var statsManager: StatsManager
+		private set
+
 	override fun onEnable()
 	{
 		instance = this
-
 		saveDefaultConfig()
-		languageManager = LanguageManager( this )
 
-		gameManager = GameManager( this )
-		antiRunningManager = AntiRunningManager( this )
+		databaseManager = DatabaseManager( this )
+		try {
+			databaseManager.connect()
+		} catch ( e: Exception ) {
+			logger.severe( "[Database] Verbindung fehlgeschlagen: ${e.message}" )
+			logger.severe( "[Database] Plugin wird deaktiviert." )
+			server.pluginManager.disablePlugin( this )
+			return
+		}
 
-		scoreboardManager = ScoreboardManager( this )
+		statsManager = StatsManager( this )
+		statsManager.initialize()
+
+		languageManager     = LanguageManager( this )
+		gameManager         = GameManager( this )
+		antiRunningManager  = AntiRunningManager( this )
+		scoreboardManager   = ScoreboardManager( this )
+		kitManager          = KitManager( this )
 
-		kitManager = KitManager( this )
 		registerKits()
-
 		registerCommands()
 		registerListener()
 
@@ -64,6 +84,8 @@ class SpeedHG : JavaPlugin() {
 
 	override fun onDisable()
 	{
+		if ( ::statsManager.isInitialized )    statsManager.shutdown()
+		if ( ::databaseManager.isInitialized ) databaseManager.disconnect()
 		kitManager.clearAll()
 		super.onDisable()
 	}
@@ -81,6 +103,8 @@ class SpeedHG : JavaPlugin() {
 		val kitCommand = KitCommand()
 		getCommand( "kit" )?.setExecutor( kitCommand )
 		getCommand( "kit" )?.tabCompleter = kitCommand
+
+		getCommand( "leaderboard" )?.setExecutor( LeaderboardCommand() )
 	}
 
 	private fun registerListener()
@@ -91,6 +115,7 @@ class SpeedHG : JavaPlugin() {
 		pm.registerEvents( GameStateListener(), this )
 		pm.registerEvents( SoupListener(), this )
 		pm.registerEvents(KitEventDispatcher( this, kitManager ), this )
+		pm.registerEvents( StatsListener(), this )
 	}
 
 }