Serve club logos directly from Caddy instead of Django

Every image request was round-tripping through a gunicorn worker
for what is just a static file on disk. Caddy now serves /media/*
straight off the shared media_data volume (mounted read-only) and
only falls through to Django for anything else — Django's own
/media/* route stays as a fallback for compose.behind-proxy.yaml
and runserver, where there is no bundled Caddy container.

compose.yaml

@@ -25,6 +25,9 @@ services:
       - ./deploy/caddy/Caddyfile:/etc/caddy/Caddyfile:ro
       - caddy_data:/data
       - caddy_config:/config
+      # Read-only: Caddy serves club logos straight off disk instead of round-tripping every
+      # image request through a gunicorn worker. Same volume `web` writes uploads into.
+      - media_data:/srv/media:ro
     depends_on:
       - web