feat: add removeVisualizer function and enhance visualizer cleanup

- Introduced `removeVisualizer` in `VisualizerManager` for better visualizer lifecycle management.
- Updated `SurfVisualizerMultipleLocationsImpl` to automatically remove visualizers when world references are invalid.
- Added `equals`, `hashCode`, and `toString` implementations for `SurfVisualizerAreaImpl` for improved object handling and debugging.

Author: twisti-dev

surf-api-bukkit/surf-api-bukkit-server/src/main/kotlin/dev/slne/surf/surfapi/bukkit/server/visualizer/visualizer/SurfVisualizerAreaImpl.kt

@@ -111,4 +111,22 @@ class SurfVisualizerAreaImpl(
             delegate.addVisualLocation(it, settings)
         }
     }
+
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is SurfVisualizerAreaImpl) return false
+
+        if (delegate != other.delegate) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return delegate.hashCode()
+    }
+
+    override fun toString(): String {
+        return "SurfVisualizerAreaImpl(useHighestYBlock=$useHighestYBlock, corners=$corners, settings=$settings)"
+    }
+
 }

surf-api-bukkit/surf-api-bukkit-server/src/main/kotlin/dev/slne/surf/surfapi/bukkit/server/visualizer/visualizer/SurfVisualizerMultipleLocationsImpl.kt

@@ -238,6 +238,7 @@ class SurfVisualizerMultipleLocationsImpl(world: World) : AbstractSurfVisualizer
             viewerUuids.clear()
             log.atWarning()
                 .log("World reference is no longer valid, stopping visualizer")
+            VisualizerManager.removeVisualizer(this)
             return false
         }
         return true

surf-api-bukkit/surf-api-bukkit-server/src/main/kotlin/dev/slne/surf/surfapi/bukkit/server/visualizer/visualizer/VisualizerManager.kt

@@ -36,6 +36,11 @@ object VisualizerManager {
         }
     }
 
+    fun removeVisualizer(visualizerImpl: AbstractSurfVisualizerImpl) {
+        activeVisualizers.values.forEach { it.remove(visualizerImpl) }
+        activeVisualizers.entries.removeIf { it.value.isEmpty() }
+    }
+
     fun processPlayerQuit(player: Player) {
         val visualizers = activeVisualizers.remove(player.uniqueId)
         visualizers?.forEach { it.removeViewer(player) }