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>

docker-compose.yml

@@ -33,6 +33,7 @@ services:
     volumes:
       - /var/run/docker.sock:/var/run/docker.sock:ro
       - ./traefik.yml:/etc/traefik/traefik.yml:ro
+      - ./docker/traefik-dynamic.yml:/etc/traefik/dynamic.yml:ro
       - acme:/etc/traefik/acme
       - certs:/etc/traefik/certs:ro
     networks:

docker/traefik-dynamic.yml

@@ -0,0 +1,17 @@
+http:
+  routers:
+    root-redirect:
+      rule: "Path(`/`)"
+      priority: 100
+      entryPoints:
+        - websecure
+      tls: {}
+      middlewares:
+        - root-to-platform
+      service: saas@docker
+  middlewares:
+    root-to-platform:
+      redirectRegex:
+        regex: "^(https?://[^/]+)/?$"
+        replacement: "${1}/platform/"
+        permanent: false

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: