docs: adopt documentation information architecture

[BotshareAI]

Summary

Publishes Documentation Information Architecture D2 as the governing framework for docs.openamrobot.ai and connects it to contribution review.

Changes

• adds the complete Documentation Information Architecture;
• publishes a concise Engineering Quality Standard overview linking to the canonical organization policy;
• exposes both standards in MkDocs navigation and the repository README;
• connects the existing Documentation Standard to the new architecture;
• updates contributor guidance and the local PR template with audience, canonical-source, verification, readiness and cross-link checks;
• replaces the generic contributing-page placeholder with the adopted manual review requirements.

Scope boundary

This PR documents the framework within the current site architecture. It does not reorganize all existing pages, introduce quality metadata, add new plugins or implement the planned CI/CD gates today.

Validation

• branch is based on current main;
• all new navigation targets exist;
• repository and site canonical-source boundaries are stated explicitly;
• no current component receives a new readiness claim through this PR.

Signed-off-by: Oleksii Reznichenko info@botshare.ai