fix: root → /platform/ redirect via Traefik file config

Docker-compose label escaping mangles regex patterns. Use a separate
Traefik dynamic config file instead — clean regex, proper 302 redirect.

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

traefik.yml

@@ -17,6 +17,8 @@ providers:
     endpoint: "unix:///var/run/docker.sock"
     exposedByDefault: false
     network: cameleer
+  file:
+    filename: /etc/traefik/dynamic.yml
 
 tls:
   stores: