Fix missing features and improve code quality

Features fixed:
- Added chat filter functionality (block/warn/censor modes)
- Fixed spy command to monitor all chat messages
- Added proper spy notifications for global/local chat

Code quality improvements:
- Created PlayerUtil to eliminate code duplication in player lookup
- Refactored ChatListener into smaller, focused methods
- Added Constants class to replace magic numbers
- Improved SOLID principles compliance
- Fixed all compilation warnings

All features from README are now implemented and working.

src/main/java/com/loki/lochat/commands/UnmuteCommand.java

@@ -13,6 +13,7 @@ import org.jetbrains.annotations.Nullable;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.UUID;
 
 /**
  * Команда /unmute nick [-s]
@@ -57,24 +58,15 @@ public class UnmuteCommand implements CommandExecutor, TabCompleter {
         }
 
         // Ищем игрока
-        Player target = Bukkit.getPlayer(targetName);
-        String finalTargetName = targetName;
-        java.util.UUID targetUUID;
-
-        if (target == null) {
-            @SuppressWarnings("deprecation")
-            var offlinePlayer = Bukkit.getOfflinePlayer(targetName);
-            if (!offlinePlayer.hasPlayedBefore() && !offlinePlayer.isOnline()) {
-                sender.sendMessage(plugin.getMessageConfig().getComponent("errors.player-not-found"));
-                return true;
-            }
-            targetUUID = offlinePlayer.getUniqueId();
-            finalTargetName = offlinePlayer.getName() != null ? offlinePlayer.getName() : targetName;
-        } else {
-            targetUUID = target.getUniqueId();
-            finalTargetName = target.getName();
+        UUID targetUUID = com.loki.lochat.utils.PlayerUtil.findPlayerUUID(targetName);
+        if (targetUUID == null) {
+            sender.sendMessage(plugin.getMessageConfig().getComponent("errors.player-not-found"));
+            return true;
         }
 
+        Player target = Bukkit.getPlayer(targetUUID);
+        String finalTargetName = com.loki.lochat.utils.PlayerUtil.getPlayerName(targetUUID);
+
         String operatorName = sender.getName();
 
         // Размучиваем