fix(animation): preserve head tracking in Full animations — head never enabled as free bone

src/main/java/com/tiedup/remake/client/gltf/GltfPoseConverter.java

@@ -605,11 +605,15 @@ public final class GltfPoseConverter {
                 } else if (
                     isFullBodyAnimation &&
                     enabledParts.contains(partName) &&
-                    partsWithKeyframes.contains(partName)
+                    partsWithKeyframes.contains(partName) &&
+                    !"head".equals(partName)
                 ) {
                     // Full-body animation: free part WITH keyframes — enable.
                     // The "Full" prefix is the artist's explicit opt-in to animate
                     // bones outside their declared regions.
+                    // EXCEPTION: head is never enabled as a free bone — vanilla head
+                    // tracking (mouse look) is always preserved unless the item
+                    // explicitly owns a head region (HEAD, EYES, EARS, MOUTH).
                     part.fullyEnablePart(false);
                 } else {
                     // Non-Full animation, other item's part, or free part without keyframes.