fix(ops): raise nginx proxy_buffer_size for the app and Supabase gateway (#330)

Supabase SSR auth sets several chunked sb-*-auth-token cookies on sign-in;
they overflow nginx's default proxy_buffer_size, which logs "upstream sent
too big header" and turns a successful login into a 502. Same fix as the
rest of dev2 (cli-tools #112). Applied to the live vhost in place, since
certbot owns its TLS lines.

Co-authored-by: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

Author: ralyodio

ops/selfhost/server/nginx-crawlproof.conf

@@ -47,6 +47,10 @@ server {
         proxy_send_timeout    300s;
         proxy_read_timeout    300s;
         proxy_buffering       off;
+        # Supabase auth cookies overflow the default header buffer (502).
+        proxy_buffer_size       64k;
+        proxy_buffers           8 64k;
+        proxy_busy_buffers_size 128k;
     }
 }
 
@@ -86,5 +90,9 @@ server {
         proxy_send_timeout    3600s;
         proxy_read_timeout    3600s;
         proxy_buffering       off;
+        # Supabase auth cookies overflow the default header buffer (502).
+        proxy_buffer_size       64k;
+        proxy_buffers           8 64k;
+        proxy_busy_buffers_size 128k;
     }
 }