Add ESG analyst workflow

[MichaelCao0]

Summary

Add an optional ESG analyst to the TradingAgents workflow and wire ESG analysis through CLI selection, graph state, report persistence, and downstream research prompts.

Changes

• Add ESG analyst selection, progress display, report rendering, and saved report output.
• Add esg_report to graph state, initial propagation, and final graph results.
• Add create_esg_analyst plus ESG score/news data tools.
• Wire ESG tool nodes and normalize analyst graph node names so ESG consistently uses ESG Analyst.
• Include ESG context in bull/bear researcher prompts.
• Harden ticker-derived CLI result paths with safe_ticker_component.
• Avoid ESG look-ahead bias by refusing current ESG scores for historical dates and filtering ESG news by curr_date.
• Add ESG integration tests for CLI registration, graph routing/compile, prompt rendering, yfinance nested news parsing, future-news filtering, and ESG DataFrame score extraction.

Testing

Remote server (eddc2d887321a8715a63ccb5ebafafaa.bayesdl.com):

python -m py_compile tradingagents/agents/analysts/esg_analyst.py tests/test_esg_integration.py
python -m pytest tests/test_esg_integration.py -q
python -m pytest tests -q

Results:

8 passed, 1 warning
116 passed, 1 warning, 42 subtests passed

Runtime smoke from the previous latest-version validation:

tradingagents --help
tradingagents analyze --help
ESG analyst node execution
ESG-only graph compile
runtime-smoke-ok

The remaining warning is an upstream LangGraph pending deprecation warning unrelated to this change.

[gemini-code-assist]

Code Review

This pull request introduces an ESG (Environmental, Social, Governance) Analyst to the trading agent system. Key changes include the implementation of an ESG analyst agent, new data tools for fetching sustainability scores and news from Yahoo Finance with look-ahead bias protection, and the integration of ESG reports into the bull and bear researcher prompts. The graph workflow and CLI have also been updated to support this new analyst type. Feedback points out a high-severity syntax error in the ESG analyst's system message definition where a trailing comma incorrectly creates a tuple, which would break the prompt formatting.