filer: stamp the rename event with the deferred copy's result

A remote-only rename over a remote-only target queued the new entry's
event with the source's stamp before the deferred copy ran. Peers
replaying it saved a stamp the copy had already superseded, and the
sync serving such a peer rejected the destination as a match and tried
to copy the deleted source. The event now carries the copy's result
and drops the pending-source marker once it lands.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

weed/server/filer_grpc_server_rename.go

@@ -208,8 +208,9 @@ func (fs *FilerServer) finishRemoteCopies(ctx context.Context, pendings []*pendi
 
 // applyRemoteCopies brings the queued rename events in line with the deferred
 // copies. The stamp is written with a plain UpdateEntry, which publishes no
-// event, so the rename event carries it to peer filers and subscribers. A
-// failed copy keeps the old object, which the entry still describes.
+// event, so the rename event carries it, without the pending-source marker,
+// to peer filers and subscribers. A failed copy keeps the old object, which
+// the entry still reads through the marker.
 func applyRemoteCopies(events []metadataEvent, pendings []*pendingRemoteCopy) {
 	for i := range events {
 		event := &events[i]
@@ -222,6 +223,8 @@ func applyRemoteCopies(events []metadataEvent, pendings []*pendingRemoteCopy) {
 			} else if pending.copied != nil && event.newEntry != nil {
 				newEntry := event.newEntry.ShallowClone()
 				newEntry.Remote = pending.copied
+				newEntry.Extended = maps.Clone(newEntry.Extended)
+				delete(newEntry.Extended, filer.ExtRemoteRenameSourceKey)
 				event.newEntry = newEntry
 			}
 		}

weed/server/filer_grpc_server_rename_remote_test.go

@@ -154,6 +154,11 @@ func TestRenameRemoteOnlyEntryOverTargetKeepsTheCopy(t *testing.T) {
 	assert.Equal(t, uint64(101), dst.Attr.Inode)
 	assert.Equal(t, `"copy"`, dst.Remote.RemoteETag)
 	assert.Empty(t, dst.Extended[filer.ExtRemoteRenameSourceKey])
+	// peers replay the post-copy state, not the source's stamp the entry
+	// committed with
+	newEvent := events[1].notification.NewEntry
+	assert.Equal(t, `"copy"`, newEvent.RemoteEntry.RemoteETag)
+	assert.Empty(t, newEvent.Extended[filer.ExtRemoteRenameSourceKey])
 }
 
 func TestRenameRemoteOnlyEntryCopyFailureKeepsTheOldObject(t *testing.T) {