Fix CSRF 403: override Origin header in Caddy proxy snippet

SvelteKit checks the browser's Origin header, not just Host or
X-Forwarded-Proto. Rewrite Origin to https://collection.newedge.house
so CSRF passes on all non-public routes (NetBird, Yggdrasil, Tor).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/caddy-reverse-proxy.md

@@ -76,6 +76,7 @@ Edit `/etc/caddy/Caddyfile`:
 (proxy) {
 	reverse_proxy 127.0.0.1:3000 {
 		header_up Host collection.newedge.house
+		header_up Origin https://collection.newedge.house
 		header_up X-Real-IP {remote_host}
 		header_up X-Forwarded-For {remote_host}
 		header_up X-Forwarded-Proto https