The Infinite HTTPS Redirect Loop That Hit Me at 2am (and How X-Forwarded-Proto Saved My Site)

Earlier this year I migrated phyfun.com from www to non- www . On paper it's a five-minute job. In practice it took the site down for several hours, generated thousands of Search Console errors, and taught me more about SiteGround's hosting stack than I ever wanted to know. This is the war story. If you're on SiteGround, or any Nginx-in-front-of-Apache hybrid setup, and you've ever wondered why your .htaccess HTTPS redirect rules don't behave the way the docs say they should — this post is for y