Add weed/parquet_pushdown/daemon, the host process for the
SeaweedParquetPushdown service:
- Config carries bind ip/port, filer addresses, trust mode, and the
ConnectorTrustedAck flag that gates the dev-only connector-trusted
trust mode (default refuses it; explicit ack required).
- filerClient probes the filer with GetFilerConfiguration at startup
so bad endpoints fail fast, mirroring the iam command's pattern.
Bounded by a 60s timeout; later milestones use the same client to
read Parquet data and side-index blobs.
- server.go wires it together: load TLS, probe filer, build the
Service, listen on (host, localhost) gRPC ports, register the
service + reflection on each, install grace.OnInterrupt for
GracefulStop, and Serve.
Run() returns an error so the calling weed pushdown command can
report startup failures instead of glog.Fatalf.