Vercel serves an existing static file before applying a rewrite, so the
previous rewrite block did nothing and the strategy docs returned 200.
Redirects run before the filesystem check, so these now leave the site.
.vercelignore does not take effect on this deployment (growth/PLAN.md
returned 200 live after being added to it), so block /.agents/* and
/growth/* with rewrites to a nonexistent path instead.