fix(supabase): use internal URL for all server-side clients with cookie name matching

ROOT CAUSE FIX: All server-side Supabase clients (server-client, middleware-client,
server-admin-client) now use SUPABASE_INTERNAL_URL (http://supabase-kong:8000)
when available, with cookieOptions.name set to match the external URL's cookie key
(e.g. sb-myeasycms-auth-token). This gives us:
- Reliable Docker-internal networking (no hairpin NAT through Traefik)
- Correct session cookie matching between browser and server
- No more 500 errors on SSR pages that query Supabase

Reverted per-page try/catch workarounds since root cause is now fixed.

docker-compose.yml

@@ -321,10 +321,12 @@ services:
     environment:
       NODE_ENV: production
       NEXT_PUBLIC_SITE_URL: ${SITE_URL:-http://localhost:3000}
-      # Same URL for browser AND server — keeps Supabase cookie names consistent
+      # Same URL for browser AND server cookie names
       NEXT_PUBLIC_SUPABASE_URL: ${API_EXTERNAL_URL:-http://localhost:8000}
       NEXT_PUBLIC_SUPABASE_PUBLIC_KEY: ${SUPABASE_ANON_KEY}
       NEXT_PUBLIC_DEFAULT_LOCALE: de
+      # Internal URL for server-side Supabase calls (Docker network, no hairpin NAT)
+      SUPABASE_INTERNAL_URL: http://supabase-kong:8000
       SUPABASE_SECRET_KEY: ${SUPABASE_SERVICE_ROLE_KEY}
       SUPABASE_DB_WEBHOOK_SECRET: ${DB_WEBHOOK_SECRET:-webhooksecret}
       EMAIL_SENDER: ${EMAIL_SENDER:-noreply@myeasycms.de}