Get project import status

Poll the status of an asynchronous project import operation.

Usage:

1. When you POST to /api/projects/{project_id}/import, you’ll receive a response like {"import": <import_id>}
2. Use that import_id with this GET endpoint to check the import status
3. Poll this endpoint to see if the import has completed, is still processing, or has failed
4. Import errors and failures will only be visible in this GET response, not in the original POST request

This endpoint returns detailed information about the import including task counts, status, and any error messages. While an import is running, task_count / annotation / prediction counts update as batches commit. Counts are cumulative so far; there is no expected total, so percent-complete / ETA is not available from this API.