Feature/remove firecrawl

[Mehranmzn]

1. Replaced the legacy Firecrawl integration with a native DuckDuckGo + Crawl4AI stack. News and SEC scraping now run through the new async LocalScrapingService (src/
2. tradegraph_financial_advisor/services/local_scraping_service.py:1), the workflow consumes it directly (src/tradegraph_financial_advisor/workflows/analysis_workflow.py:39), docs/env/deps were
3. updated to remove Firecrawl references (README.md:4, .env.example:1, pyproject.toml:5, requirements.txt:1, docs/index.md:6), and the old Firecrawl service file was deleted. Tests and fixtures
4. were refreshed to cover the new scraping behavior (tests/unit/test_workflows.py:120, tests/unit/test_agents.py:214, tests/conftest.py:1), with uv.lock capturing the dependency refresh.
5. Added first-class support for choosing the OpenAI model: the workflow, trading engine, and report analyzer accept an llm_model_name (default gpt-5-nano), and FinancialAdvisor wires it
6. through (src/tradegraph_financial_advisor/workflows/analysis_workflow.py:39, src/tradegraph_financial_advisor/agents/recommendation_engine.py:23, src/tradegraph_financial_advisor/agents/
7. report_analysis_agent.py:16, src/tradegraph_financial_advisor/main.py:17).
8. Tests: uv run pytest tests (pass).
9. Pre-commit hooks were run, but ruff, mypy, and bandit still report outstanding issues (unused variables, missing type annotations in api/*, bandit CLI args). These need addressing before