docs: establish WaveBench documentation workflow

[Scaxlibur]

Summary

• add the repo-local wavebench-docs skill with audit, migrate, write, and diff-focused review modes
• establish canonical-source, Core/plugin, document lifecycle, and collaboration-output rules
• reorganize current documentation into task-oriented entry points while preserving short compatibility pages and historical archives
• add deterministic documentation auditing, generated run-schema reference checks, diff-impact guidance, and CI integration
• add a MkDocs Material site configuration and refresh the README landing page

Validation

• full documentation audit: 0 errors; 9 accepted historical, long-page, navigation, or README H1 warnings
• pytest -q tests/test_docs_audit.py tests/test_docs_generation.py tests/test_docs_impact.py: 10 passed
• python scripts/generate_docs.py --check
• python -m mkdocs build --strict
• repository skill validation and Chinese documentation style checks
• git diff --check

Safety and scope

• no live instruments were connected
• no local bench configuration or experimental data was modified
• this PR does not enable or deploy GitHub Pages