Add get_client_ip() helper that inspects Forwarded and X-Forwarded-For
headers only when the direct peer is in TRUSTED_PROXIES (comma-separated
IPs/CIDRs). Replaces raw request.client.host in rate-limit and webhook
source_ip to prevent all traffic collapsing behind a reverse proxy IP.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>