refactor: clean up config - rename fields, remove redundant server fields, drop migrations

- Rename QueueTypeConfiguration.order → priority (higher = higher priority)
- Rename QueueTypeConfiguration.slots → reservedSlots for clarity
- Mark singular queueServer/targetServer/sourceServer as @ignore (use queue groups instead)
- Remove ConfigMigrator and all migration code (no released version to migrate from)
- Fix rebuildKickWhenDownServers to use resolved queue groups with fallback values
- Fix postProcess order: build types and groups before resolving kick-when-down servers
- Simplify QueueEnvironment by removing singular-field fallbacks
- Update all tests to use queue group helpers instead of removed singular accessors

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: AlexProgrammerDE

shared/src/main/java/net/pistonmaster/pistonqueue/shared/config/Config.java

@@ -25,7 +25,6 @@
 import de.exlll.configlib.YamlConfigurations;
 import net.pistonmaster.pistonqueue.shared.chat.MessageType;
 import net.pistonmaster.pistonqueue.shared.config.Config;
-import net.pistonmaster.pistonqueue.shared.config.ConfigMigrator;
 import net.pistonmaster.pistonqueue.shared.queue.QueueGroup;
 import net.pistonmaster.pistonqueue.shared.queue.QueueListenerShared;
 import net.pistonmaster.pistonqueue.shared.queue.QueueType;
@@ -71,18 +70,7 @@ public interface PistonQueuePlugin {
 
   default void scheduleTasks(QueueListenerShared queueListener) {
     Config config = getConfiguration();
-    QueueGroup resolvedDefaultGroup = config.getDefaultGroup();
-    if (resolvedDefaultGroup == null) {
-      List<QueueType> queueTypes = config.getAllQueueTypes();
-      resolvedDefaultGroup = new QueueGroup(
-        "default",
-        Collections.singletonList(config.queueServer()),
-        Collections.singletonList(config.targetServer()),
-        config.enableSourceServer() ? Collections.singletonList(config.sourceServer()) : Collections.emptyList(),
-        queueTypes
-      );
-    }
-    final QueueGroup defaultGroup = resolvedDefaultGroup;
+    final QueueGroup defaultGroup = config.getDefaultGroup();
     // Sends the position message and updates tab on an interval in chat
     schedule(() -> {
       boolean targetsOnline = defaultGroup.targetServers().stream().anyMatch(queueListener.getServerStatusManager().getOnlineServers()::contains);
@@ -305,8 +293,7 @@ default void processConfig(Path dataDirectory) {
     }
   }
 
-  default void loadConfig(Path file) throws IOException {
-    ConfigMigrator.migrate(file);
+  default void loadConfig(Path file) {
     Config loaded = YamlConfigurations.update(
       file,
       Config.class,

shared/src/main/java/net/pistonmaster/pistonqueue/shared/config/ConfigMigrator.java

@@ -47,7 +47,7 @@ public class QueueType {
   private final AtomicInteger playersWithTypeInTarget = new AtomicInteger();
   private final String name;
   @Setter
-  private volatile int order;
+  private volatile int priority;
   @Setter
   private String permission;
   @Setter

shared/src/main/java/net/pistonmaster/pistonqueue/shared/plugin/PistonQueuePlugin.java

@@ -25,7 +25,6 @@
 import net.pistonmaster.pistonqueue.shared.queue.QueueGroup;
 import net.pistonmaster.pistonqueue.shared.queue.QueueType;
 
-import java.util.List;
 import java.util.Objects;
 import java.util.Set;
 import java.util.function.Supplier;
@@ -57,20 +56,7 @@ public Set<String> onlineServers() {
   }
 
   public QueueGroup defaultGroup() {
-    Config config = config();
-    QueueGroup group = config.getDefaultGroup();
-    if (group != null) {
-      return group;
-    }
-
-    List<QueueType> queueTypes = config.getAllQueueTypes();
-    return new QueueGroup(
-      "default",
-      List.of(config.queueServer()),
-      List.of(config.targetServer()),
-      config.enableSourceServer() ? List.of(config.sourceServer()) : List.of(),
-      queueTypes
-    );
+    return config().getDefaultGroup();
   }
 
   public QueueGroup resolveGroupForTarget(String server) {
@@ -86,9 +72,6 @@ public QueueGroup resolveGroupForType(QueueType type) {
   }
 
   public String defaultTarget(QueueGroup group) {
-    if (group.targetServers().isEmpty()) {
-      return config().targetServer();
-    }
     return group.targetServers().getFirst();
   }