Add AI overview landing page with decision table and relationship overview.
Reframe Gordon as "AI-powered assistant" instead of "AI agent" to avoid
confusion with Docker Agent. Rename sandbox agent page from cagent.md to
docker-agent.md. Add cross-references where products overlap. Fix doubled
"Docker Docker Agent" in agentic AI guide.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Signed-off-by: David Karlsson <35727626+dvdksn@users.noreply.github.com>