Replace the liquidity heuristic in score_symbols with a real GetEnsembleVote gRPC call to trading-service. Each symbol gets a concurrent RPC; on failure the original liquidity*0.9+0.1 heuristic is used as fallback. The ML client is lazily initialized via OnceCell and the service URL is configurable via ML_SERVICE_URL env var. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>