Documents the fleet's WP Offload Media pattern (warrior/stray MinIO,
dedicated bucket per site, WPS3Media plugin) and an open production bug
found while applying it to sateulera-dev: the public S3 API endpoint
(Caddy -> warrior) currently rejects all signed writes, unrelated to
credentials or plugin config.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
