Centralize reviews and suite-owned automation

[gpBlockchain]

Summary

• centralize reviewer-facing case documents under root reviews/
• generate executable automation and fixtures under suites/<suite>/, including single-suite projects
• make the mapping checker resolve the project root from its script path and scan nested case/ directories
• update templates, guidance, and regression coverage for the unified layout

Verification

• PYTHONDONTWRITEBYTECODE=1 python3 -m unittest discover -s tests -v (13 tests passed)
• git diff --cached --check