Migrate the Nix build + deploy source from /home/code/9router-repo (a pure
upstream mirror, now deleted) to this repo, which carries the MIBP fork
merge (freebuff, cline free models, proxy-pool fitness). flake.lock and
flake.nix copied verbatim from 9router-repo; bun.lock generated from the
merged dependency set. The cron updater (9router-update.sh) now points at
/home/code/9router with a keep-ours conflict policy.
