fix: ensure snapshot() holds read lock during deep copy

Co-authored-by: twisti-dev <[email protected]>

Author: Copilot

surf-cloud-core/surf-cloud-core-common/src/main/kotlin/dev/slne/surf/cloud/core/common/player/CommonCloudPlayerImpl.kt

@@ -22,6 +22,7 @@ abstract class CommonCloudPlayerImpl(uuid: UUID, override val name: String) :
     protected val persistentDataView = object : PersistentPlayerDataContainerViewImpl() {
         override fun toTagCompound() = ppdcReentrantLock.read { ppdc.tag }
         override fun getTag(key: String) = ppdcReentrantLock.read { ppdc.getTag(key) }
+        override fun snapshotTag() = ppdcReentrantLock.read { super.snapshotTag() }
     }
 
     override val persistentData get() = persistentDataView

surf-cloud-core/surf-cloud-core-common/src/main/kotlin/dev/slne/surf/cloud/core/common/player/ppdc/PersistentPlayerDataContainerViewImpl.kt

@@ -114,18 +114,27 @@ abstract class PersistentPlayerDataContainerViewImpl : PersistentPlayerDataConta
     }
 
     override fun snapshot(): PersistentPlayerDataContainerViewImpl {
-        val tag = deepCopy(toTagCompound())
-
-        val tagCopy = CompoundBinaryTag.builder()
-            .put(tag)
-            .build()
+        val tagCopy = snapshotTag()
 
         return object : PersistentPlayerDataContainerViewImpl() {
             override fun toTagCompound() = tagCopy
             override fun getTag(key: String) = tagCopy.get(key)
+            override fun snapshotTag() = tagCopy
         }
     }
 
+    /**
+     * Creates a snapshot of the tag compound.
+     * Subclasses should override this method to ensure the snapshot is created
+     * while holding appropriate locks to prevent concurrent modifications.
+     */
+    protected open fun snapshotTag(): CompoundBinaryTag {
+        val tag = deepCopy(toTagCompound())
+        return CompoundBinaryTag.builder()
+            .put(tag)
+            .build()
+    }
+
 
     /**
      * Creates a deep copy of the provided `CompoundBinaryTag` without using recursion.