Replace last 2 stub gRPC handlers with real implementations:
- GenerateOrders: loads allocation, generates orders via OrderGenerator with
ML signal context, contract price estimation, and dynamic stop-loss
- SubmitAgentOrders: validates orders, supports dry_run mode, persists to
agent_orders table with full metadata
Trading agent service: 15/15 endpoints now have real implementations.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>