Handle LongBridge quote limits and sub-share orders

[Pigbibi]

Summary

• batch LongBridge position quote reads and retry transient 301606 rate-limit responses
• reject sub-1-share LongBridge orders locally before calling the broker API
• add focused LongBridge market data, portfolio, and execution coverage

Tests

• PYTHONPATH=src /home/ubuntu/Projects/LongBridgePlatform/.venv/bin/python -m pytest tests/test_longbridge_market_data.py tests/test_longbridge_portfolio.py tests/test_longbridge_execution.py
• PYTHONPATH=src /home/ubuntu/Projects/LongBridgePlatform/.venv/bin/python -m ruff check src/quant_platform_kit/longbridge tests/test_longbridge_market_data.py tests/test_longbridge_portfolio.py tests/test_longbridge_execution.py

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: b0fe062569

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[chatgpt-codex-connector]

Chunk quote calls to LongBridge's 500-symbol request cap

fetch_last_prices sends the entire deduplicated symbol list in one q_ctx.quote(...) call, but LongBridge's quote API accepts at most 500 symbols per request. When fetch_strategy_account_state passes a portfolio with more than 500 distinct holdings, this call will fail and the whole account snapshot path raises instead of returning values; before this change, per-symbol quote calls did not hit that hard cap. Please split normalized_symbols into <=500 batches and merge results.

Useful? React with 👍 / 👎.