NEW-1: add_header in location /api block suppressed server-level security headers (HSTS, CSP, X-Frame-Options, etc). Duplicate all security headers into the /api block explicitly per nginx inheritance rules. NEW-2: Add 0.0.0.0/8 to _BLOCKED_NETWORKS — on Linux 0.0.0.0 connects to localhost, bypassing the existing loopback check. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>