v0.1.89 - Update Platform API contract (#118)

🌟 Summary

Version 0.1.89 updates the Ultralytics Platform API and Python SDK with an optional link to a model returned during training callbacks.

📊 Key Changes

• 🔗 Added the optional modelUrl field to training callback responses and the Python TrainingMetricsResponse type. It points to the registered model’s page on the Platform.
• 📚 Updated the training API documentation and SDK descriptions to explain the new field.
• 📦 Synchronized the OpenAPI contract and Python SDK versions at 0.1.89 and refreshed the contract checksum.

🎯 Purpose & Impact

• 🧭 Training integrations can use modelUrl to take users directly to their model on the Platform.
• ✅ The field is optional, so existing integrations can continue working without changes.
• 🧩 This release updates the API contract and SDK; it does not introduce model architecture or training changes.

What's Changed

• Update Platform API contract by @UltralyticsAssistant in #118

Full Changelog: v0.1.88...v0.1.89