Remove Traefik — use simple port binding for NPM

Stack uses Tailscale + Nginx Proxy Manager, not Traefik.
Client exposes PORT (default 3080) for NPM to proxy to.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.env.example

@@ -12,5 +12,8 @@ POSTGRES_PASSWORD=change-this-to-a-strong-password
 # Generate with: openssl rand -hex 64
 JWT_SECRET=change-this-to-a-long-random-string
 
-# Fully-qualified domain — must match your Traefik routing rule
-DOMAIN=tickets.thewrightserver.net
+# Origin NPM proxies to this app (used for CORS)
+CLIENT_URL=http://tickets.thewrightserver.net
+
+# Host port NPM proxies to — change if 3080 is taken
+PORT=3080