setfetterlevel command

src/main/java/emu/grasscutter/command/commands/SetFetterLevelCommand.java

+package emu.grasscutter.command.commands;
+
+import java.util.List;
+
+import emu.grasscutter.command.Command;
+import emu.grasscutter.command.CommandHandler;
+import emu.grasscutter.game.GenshinPlayer;
+import emu.grasscutter.game.entity.EntityAvatar;
+
+@Command(label = "setfetterlevel", usage = "setfetterlevel <level>",
+        description = "Sets your fetter level for your current active character",
+        aliases = {"setfetterlvl"}, permission = "player.setfetterlevel")
+public final class SetFetterLevelCommand implements CommandHandler {
+
+    @Override
+    public void execute(GenshinPlayer sender, List<String> args) {
+        if (sender == null) {
+            CommandHandler.sendMessage(null, "Run this command in-game.");
+            return;
+        }
+
+        if (args.size() < 1) {
+            CommandHandler.sendMessage(sender, "Usage: setfetterlevel <level>");
+            return;
+        }
+
+        try {
+            int fetterLevel = Integer.parseInt(args.get(0));
+            if (fetterLevel < 0 || fetterLevel > 10) {
+                CommandHandler.sendMessage(sender, "Fetter level must be between 0 and 10.");
+                return;
+            }
+            EntityAvatar avatar = sender.getTeamManager().getCurrentAvatarEntity();
+            avatar.getAvatar().setFetterLevel(fetterLevel);
+            CommandHandler.sendMessage(sender, "Fetter level set to " + fetterLevel);
+        } catch (NumberFormatException ignored) {
+            CommandHandler.sendMessage(null, "Invalid fetter level.");
+        }
+    }
+    
+}

src/main/java/emu/grasscutter/game/managers/InventoryManager.java

@@ -713,7 +713,7 @@ public class InventoryManager {
 
 	public void upgradeAvatarFetterLevel(GenshinPlayer player, GenshinAvatar avatar, int expGain) {
 		// May work. Not test.
-		int maxLevel = GenshinData.getAvatarFetterLevelDataMap().get(GenshinData.getAvatarFetterLevelDataMap().size() - 1).getLevel();
+		int maxLevel = 10; // Keep it until I think of a more "elegant" way
 		int level = avatar.getFetterLevel();
 		int exp = avatar.getFetterExp();
 		int reqExp = GenshinData.getAvatarFetterLevelExpRequired(level);