3.10 — Landing page: remove fabricated stats and dead links

Phase: 3 — Delivery Tree (Surface E) Stage: GREEN

Delete fabricated stats in app/page.tsx ("40% CPU reduction", "99.2% uptime", "Mission-critical", "60% latency cut") — wire each card to a real number from /api/topology or /api/delivery, or remove the claim
Five of six landing cards link to routes that don't exist (/infrastructure, /systems, /llm, /kafka, /opensource) — fix or remove