Testing Documentation: Restructure and Standardize Documentation Framework

## Summary

Restructure and standardize the testing documentation to improve discoverability, maintainability, and clarity.

## Requirements

- Create a comprehensive README.md for testing documentation
- Standardize document naming conventions
- Add consistent structure (Overview, Purpose, Use When) to all documents
- Improve navigation and cross-referencing between documents
- Update all testing documentation to follow new standards

## Motivation

The testing documentation needs better organization and structure to:
- Make it easier for contributors to find relevant information
- Provide clear guidance on when to use each document
- Establish consistent patterns for future documentation
- Improve maintainability and discoverability

## Acceptance Criteria

- [ ] New README.md with comprehensive overview and navigation
- [ ] All documents follow consistent naming convention
- [ ] All documents have standardized structure (Overview, Purpose, Use When)
- [ ] Clear cross-references between related documents
- [ ] Updated documentation standards and contribution guidelines
- [ ] All changes committed and pushed

## Reference

This work improves the testing documentation framework established in previous testing infrastructure work.