feat(blueprints): add direct upload registration

[jason-rl]

Summary

• add blueprints.register() for creating a blueprint that awaits a direct image upload
• expose generated request and response types, including push_reference
• add awaiting_upload to the blueprint lifecycle type and polling behavior
• keep registration tests hermetic while the published OpenAPI mock catches up

Testing

• node ./node_modules/jest/bin/jest.js tests/api-resources/blueprints.test.ts --runInBand (20 passed against the default CI mock)
• ./scripts/lint (Node 22)
• ./scripts/build (Node 22)