Document every GT Performance feature 25 pages covering the page cache and its decision rules, cache exclusions, Private Islands, commerce safety, CSS and JavaScript optimization, media, fonts and embeds, Cloudflare, CDN, xCloud, Redis, Fleet, database cleanup, integrations, diagnostics and troubleshooting, plus full WP-CLI, settings, hooks and constants references, an architecture page explaining the drop-in contract and the inert-JSON config format, and an upgrade guide for the pre-1.0.1 migration. Written from the source rather than the readme, so it documents the parts that actually trip people up: why an unknown query parameter bypasses rather than caching, why the drop-in and WordPress must sanitize identically, why the configuration files keep a .php extension, and why installing the Redis drop-in refuses when it cannot connect. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>