Mount AUDIOFILES_PATH to same path inside container

Previously AUDIOFILES_PATH=/media was mounted as /audiofiles in the
container, so the file browser showed /audiofiles instead of /media.
Now the host path is preserved inside the container, so /media stays
/media. The default (./audiofiles) still maps to /audiofiles.

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

docker-compose.yml

@@ -6,7 +6,7 @@ services:
     env_file: .env
     volumes:
       - ./data:/app/data
-      - ${AUDIOFILES_PATH:-./audiofiles}:/audiofiles:ro
+      - ${AUDIOFILES_PATH:-./audiofiles}:${AUDIOFILES_PATH:-/audiofiles}:ro
     expose:
       - "8000"
     depends_on: []