fix: SQLite readonly error in Docker container

- Add entrypoint script that ensures /data is owned by node user
  before dropping privileges with su-exec
- Remove USER node from Dockerfile (entrypoint handles it)
- Change client depends_on to service_healthy so nginx waits for
  the server to pass its healthcheck before starting

web/docker-compose.yml

@@ -27,7 +27,7 @@ services:
       - inventory-network
     depends_on:
       server:
-        condition: service_started
+        condition: service_healthy
     restart: unless-stopped
 
 networks: