Complete docstring coverage following PEP 257

[moshesham]

Problem

Several functions and modules lack docstrings:

• infra/logging_config.py - Missing module and class docstrings
• SQl_answer.py - Missing function docstrings
• Various helper methods lack documentation

Impact

• Harder for new contributors to understand code
• Poor IDE documentation support
• Not following PEP 257
• Difficult to generate API documentation

Tasks

• Add module docstrings to all Python files
• Add class docstrings with Attributes section
• Add method docstrings with Args, Returns, Raises
• Add docstrings to infra/logging_config.py
• Add docstrings to SQl_answer.py
• Review existing docstrings for completeness
• Add examples in docstrings where helpful
• Run docstring linter: pydocstyle infra/
• Generate API docs with sphinx to verify

References

• PROJECT_REVIEW.md Issue Add requirements-dev.txt for development dependencies #10
• PEP 257: https://www.python.org/dev/peps/pep-0257/