The empty-prefix middleware shared per-IP buckets with verify-totp,
password change, and the sensitive endpoints, so a client's 30/min
auto-poll could 429 its own user's 2FA or password change. Dedicated
"client_update:" prefix, mirroring "livekit_proxy:".
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>