feat: launch llmdoc website and documentation

[pDJJq]

Summary

• add a standalone Astro website with English and Chinese landing pages and documentation
• explain the Context Floor, retrieval model, knowledge gates, workflows, and CLI surface through a responsive static site
• keep Viewer functionality local to llmdoc serve; the website does not read repositories or introduce a remote Viewer/data plane
• configure Cloudflare Workers Static Assets for llmdoc.tokenroll.ai
• add a stable llmdoc owner for the website product and deployment boundary

Verification

• npm --prefix website run check
• npm --prefix website run build
• npm --prefix website run cf:dry-run
• npm run lint
• npm run typecheck
• npm test (53 tests)
• npm run check:prompts
• npm run validate:dogfood
• npx -y @tokenroll/llmdoc validate
• final llmdoc delta: 0 impacted, 0 needs-review
• desktop and mobile browser QA; production console: 0 errors/warnings

Deployment

The static site is live at https://llmdoc.tokenroll.ai/. The previous Pages project remains available as a rollback surface.