- Create EnsembleModelAdapter in ml::ensemble wrapping model IDs - Add build_production_strategy() factory: 10-model ensemble with ProductionFeatureExtractorAdapter + graceful degradation (zero confidence when no checkpoints loaded) - Wire backtesting_service to use the factory function - Harden metrics HTTP server: 5s read timeout, 8KB request limit, correct Content-Type charset=utf-8 Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>