Docs: reflect the 2026-08-18 second swap (rename + Qwen3.6 restore)
- AGENTS.md: topology table, second-swap note, benchmark policy service
names, mark FastMTP section retired, update model-load quirk.
- docs/index.md: intro, topology diagram, active-deployment + CIRU
reference service names.
- docs/deployment.md: overview table, manual-update paths, rewrite both
service-unit descriptions (Dankserver=Qwen3.6 Q6_K_P frank-default-small,
Dankclaw=CIRU frank-default-large), validation model name.