X-Forwarded-For, X-Real-IP, and CF-Connecting-IP headers were blindly trusted, allowing attackers to bypass rate limiting by spoofing different IPs. Now only trusted when TRUSTED_PROXY env var is configured. Falls back to Node.js socket remoteAddress. Add tests verifying proxy headers are ignored without TRUSTED_PROXY and respected when it is set. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>