Support API key configuration for Zerox in multi-tenant setup

We are currently using Zerox for document transformation in our system. However, Zerox only supports reading the API key from environment variables.

Our platform is multi-tenant, and the API key is scoped per project. This makes it problematic to rely solely on environment variables for API key management.

We already opened a PR in the Zerox repo to add support for passing the API key explicitly instead of always fetching it from environment variables. However, in case we don’t receive a response from the maintainers, we will need to either:

• Move to another tool that supports this flexibility, or
• Implement a workaround where each Celery worker handles project-specific API keys.

Context:

Each Celery worker runs in a separate process, which means separate memory and environment, so we can set api_key in env.

Test:
Once fixed this add unit tests for transfomer

Bắt đầu bằng cách xác định integration của Zerox và khu vực unit-test của transformer trong Python backend. Kiểm tra xem upstream API-key PR có sẵn hay không, sau đó xác định cách các project-scoped keys phải được truyền đến transformer; được coi là hoàn tất khi cách tiếp cận đã chọn hoạt động cho việc sử dụng multi-tenant và có unit tests cho transformer.