IP-based rate limiting fails behind reverse proxy

When Meilisearch runs behind a reverse proxy, IP-based rate limiting sees all requests as originating from the proxy's IP address, accidentally applying a global rate limit to all users instead of per-user limits.

Configure rate limiting by API key or tenant token instead of source IP when the instance is deployed behind a reverse proxy. Use actix-governor extractors to enable API-key-based limiting. Document this requirement in production deployment guides. When no proxy is present, IP-based rate limiting remains effective as first-line defense.