Add Futu OpenAPI integration for HK and US trading

[dl-sdu]

Summary

• add Futu market-data and simulated/live trading support for HK and US stocks, including credentials, symbol mapping, API routes, and strategy execution
• harden private execution streams and REST reconciliation against duplicate fills, reconnect races, and missed ledger projections
• add a secure WSL/Docker OpenD bridge that keeps the gateway loopback-only and avoids SDK/relay connection leaks

Test plan

• Run Futu-focused regression suite: 45 passed, 1 skipped
• Run execution-stream and ledger regression suite: 26 passed
• Validate Docker Compose services and container-to-OpenD quote/trade permissions
• Complete an HK simulated Tencent round trip (buy 100 at 456.60, sell 100 at 456.80) and verify PostgreSQL ledger reconciliation and zero final position