fix: voice drop zone was swallowing channel reorder drops

handleVoiceDropZoneDrop called stopPropagation and clearState
unconditionally, preventing container's handleContainerDrop from
firing when dropping a channel onto a voice channel. Add early
return for non-voiceUser drags so channel/category drops bubble
through to the container handler correctly.

packages/web/src/hooks/useDragManager.ts

@@ -180,9 +180,11 @@ export function useDragManager(opts: UseDragManagerOpts) {
   }, [activeDrag]);
 
   const handleVoiceDropZoneDrop = useCallback((e: React.DragEvent, channelId: string) => {
+    // Only handle voice user drops — let channel/category drops bubble to container
+    if (activeDrag?.type !== 'voiceUser') return;
     e.preventDefault();
     e.stopPropagation(); // Prevent bubbling to container's onDrop
-    if (activeDrag?.type === 'voiceUser' && activeDrag.sourceId && activeDrag.sourceId !== channelId) {
+    if (activeDrag.sourceId && activeDrag.sourceId !== channelId) {
       onVoiceUserDrop(activeDrag.dragId, activeDrag.sourceId, channelId);
     }
     clearState();