Simplify user-facing method documentation

[dcajal]

Summary

• replace separate specification and scientific-note pages with one practical page per method
• generate interface tables, references, and technical links during the MkDocs build
• reduce the public navigation to Home, Methods, Implementations, and Cite
• remove public conformance-case tables and historical implementation commentary
• simplify repository guidance and contribution documentation

Impact

Users now have one place to understand a method, its inputs and outputs, scientific context, limitations, references, and implementation links. Normative JSON specifications and shared cases remain available as technical resources without being duplicated in the public site.

Translation support is intentionally outside this change.

Validation

• .venv\Scripts\python.exe -m compileall tools
• .venv\Scripts\python.exe -m unittest discover -s tests -v (16 passed)
• .venv\Scripts\python.exe tools\validate_specs.py
• .venv\Scripts\python.exe -m mkdocs build --strict
• git diff --check