Makes the cloud DX forge shortcuts (mcforge, ctforge) first-class citizens of the shared net-tools layer:
- New bin/forge-dns-render (print/install/diff) that sources ~/.vault/*_forge_creds and emits a managed # >>> dx-forges block in /etc/hosts.
- `net sync` now also converges the DX forges (alongside mesh-hosts + ssh).
- Per-project ./run forge:dns now prefers the central renderer (with local fallback).
- Docs updated.
The mcforge:3000 / ctforge:3000 shortcuts are now installed and kept fresh as part of standard DX infra setup (`net sync` after net-tools install, or after any forge:up).
