[SandObserver]

Summary

• Delete docs/screenshots.md; keep every docs/*.png, which templates/stackyard.xml and the Docker Hub header pull from raw.githubusercontent.com.
• Replace docs/support.md with a stub pointing at the site's Support and Troubleshooting pages, keeping the URL shipped in released images resolvable.
• Slim README.md to a landing card: drop the table of contents, the badge and icon sections, the docker run sample and the build-from-source steps, and add a Documentation link list.
• Retarget the Documentation and Support rows in Settings, About at the documentation site.
• Point the generated Docker Hub header at the documentation site for docs, and at GitHub for source and issues.

Testing
All green, including the Docker build. No new tests; dockerhub-description and pwa-claims already pin the README claims this touches.

Checklist

• Stays within the project constraints: one container, no runtime dependencies, no build step (see CONTRIBUTING.md).
• Tests added or updated for new logic, and the full suite, lint, and typechecks pass.
• Docs updated if behavior or configuration changed.
• CHANGELOG.md updated under Unreleased if the change is user-visible.