channels.nixos.org is unreachable from CN, causing 25s of
retries on every nix-shell/nix run invocation.
Co-Authored-By: Claude Opus 4.6 <[email protected]>
cache.nixos.org has ~1.1s latency from CN. TUNA mirror responds
in ~29ms (38x faster). Set connect-timeout=5 and
stalled-download-timeout=15 to fail fast on unreachable mirrors.
Also add btop to skydick monitoring packages.
Co-Authored-By: Claude Opus 4.6 <[email protected]>
Unified NixOS configuration for skydick (storage server) and
xlab-gateway (lab router). Flat module structure with shared
common/users/ssh modules, agenix secrets, disko, and deploy-rs.
Co-Authored-By: Claude Opus 4.6 <[email protected]>
