- Updated API routes to use app_id instead of sandbox_id for file operations, aligning with user-specific sandbox workspaces.
- Enhanced SandboxFileService and related classes to accommodate app_id in file listing and download functionalities.
- Refactored storage key generation for sandbox archives to include app_id, ensuring proper file organization.
- Adjusted frontend contracts and services to reflect the new app_id parameter in API calls.
- Add BundleManifest with dsl_filename for 100% tree ID restoration
- Implement two-step import flow: prepare (get upload URL) + confirm
- Use sandbox for zip extraction and file upload via presigned URLs
- Store import session in Redis with 1h TTL
- Add SandboxUploadItem for symmetric download/upload API
- Remove legacy source_zip_extractor, inline logic in service
- Update frontend to use new prepare/confirm API flow
