Add LobbyItemManager; PDC support; misc fixes

Introduce LobbyItemManager to provide interactive lobby hotbar items (kits & perks) tagged via PersistentDataContainer and open the appropriate GUIs. Wire the manager into SpeedHG (field, init, event registration) and clear lobby items at game start in GameManager. Add ItemBuilder.pdc helper and necessary imports for setting PDC. Fix potion duration calculation to use invincibilityTime*20. Change AnchorKit icon/trigger material to ANVIL. Update config (border start/end/shrink and disable anti-runner) and update en_US language entries (lobby item names, leaderboard format, kit lore/formatting and small text fixes).

src/main/kotlin/club/mcscrims/speedhg/util/ItemBuilder.kt

@@ -5,9 +5,11 @@ import net.kyori.adventure.text.format.TextDecoration
 import net.kyori.adventure.text.minimessage.MiniMessage
 import org.bukkit.ChatColor
 import org.bukkit.Material
+import org.bukkit.NamespacedKey
 import org.bukkit.enchantments.Enchantment
 import org.bukkit.inventory.ItemFlag
 import org.bukkit.inventory.ItemStack
+import org.bukkit.persistence.PersistentDataType
 
 class ItemBuilder(
 	private val itemStack: ItemStack
@@ -76,6 +78,18 @@ class ItemBuilder(
 		return this
 	}
 
+	fun <T, Z> pdc(
+		key: NamespacedKey,
+		dataType: PersistentDataType<T, Z>,
+		value: Z
+	): ItemBuilder
+	{
+		itemStack.editMeta {
+			it.persistentDataContainer.set( key, dataType, value!! )
+		}
+		return this
+	}
+
 	fun enchant(
 		ench: Enchantment
 	): ItemBuilder