fix: config.json lives in data dir, not bind-mounted as file

Removes the separate config.json file bind mount from both compose
files. The data directory mount already covers it, and the Go server
searches /app/data/config.json via LoadConfig.

- Entrypoint symlinks /app/data/config.json for ingestor compatibility
- manage.sh setup creates config in data dir, prompts admin if missing
- manage.sh start checks config exists before starting, offers to create
- deploy.yml simplified — no more sudo rm or directory cleanup
- Backup/restore updated to use data dir path

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

docker-compose.yml

@@ -21,7 +21,6 @@ services:
       - "${PROD_HTTPS_PORT:-443}:443"
       - "${PROD_MQTT_PORT:-1883}:1883"
     volumes:
-      - ./config.json:/app/config.json:ro
       - ./caddy-config/Caddyfile:/etc/caddy/Caddyfile:ro
       - ${PROD_DATA_DIR:-~/meshcore-data}:/app/data
       - caddy-data:/data/caddy