s3: dial the object lock's primary filer directly

The S3 object write lock builds a fresh short-lived lock per write, each
starting at the seed filer. When the seed isn't the key's hash-ring primary
the filer forwards the request to the primary, and in multi-cluster setups
that forward crosses clusters on every write.

Give the lock client a view of the filer lock ring, fed by the master's
LockRingUpdate broadcasts the gateway already receives, so it dials the
primary directly. The view tracks filer membership by version; a stale view
stays correct because the filer still forwards as a fallback.

Also send the initial ring snapshot to S3 clients, not just filers.

weed/server/master_grpc_server.go

@@ -393,7 +393,13 @@ func (ms *MasterServer) KeepConnected(stream master_pb.Seaweed_KeepConnectedServ
 }
 
 func (ms *MasterServer) initialLockRingUpdate(clientType string, filerGroup string) *master_pb.KeepConnectedResponse {
-	if clientType != cluster.FilerType || ms.LockRingManager == nil {
+	if ms.LockRingManager == nil {
+		return nil
+	}
+	// Filers are ring members; S3 gateways are lock clients that need the same
+	// view to dial a key's primary directly. Both get the initial snapshot;
+	// later membership changes already broadcast to every connected client.
+	if clientType != cluster.FilerType && clientType != cluster.S3Type {
 		return nil
 	}