The plugin cluster context forwarded filers as gRPC-only addresses
(host:grpcPort). The admin-script worker stored that in
ShellOptions.FilerAddress, whose shell commands re-derive the gRPC port
via ToGrpcAddress() and re-add the +10000 offset, dialing a non-existent
host:28888.
Carry filers in pb.ServerAddress form (host:httpPort.grpcPort) and let
each consumer convert when it dials: the admin shell uses it verbatim,
while the s3_lifecycle and iceberg workers collapse it to a gRPC address.
Rename the proto field filer_grpc_addresses -> filer_addresses so the
name matches the content.
87fdea5330