Turn Weave routing off

When the user invokes $router-off, switch this Codex installation off the
Weave Router without logging out or deleting its router configuration.

Run exactly:

npx --package @weave-os/router -y -- weave-router off --codex{{SCOPE}}

Then report the result and tell the user the change takes effect on their next
codex launch — Codex reads its provider config at startup, so the current
session keeps routing as it already was. It can be reversed with
$router-on. Do not uninstall the router or alter any other Codex settings.