Fix: Added 'training_status' property to MLModel(#491)

[zenowinged]

Change(s)

Added a 'training_status' property to MLModel.
Change Type: Added

Change Category: Interface

Changelog Entry:
Added the missing training_status property to the MLModel schema.

This ensures the API implementation is fully aligned with the latest conceptual model export.

How to Test

You can verify this change by running the schema comparison script against the latest model export:
python3 scripts/model_comparison/compare.py src scripts/model_comparison/model-export.json --class "MLModel"
(This now correctly outputs zero differences).

Checklist

• Tests have been added or updated to reflect the changes, or their absence is explicitly explained. (Absence explained: Verified via the existing compare.py schema validation).
• Documentation has been added or updated to reflect the changes, or their absence is explicitly explained. (Absence explained: No manual documentation changes required; schema sync only).
• A self-review has been conducted checking:
  • No unintended changes have been committed.
  • The changes in isolation seem reasonable.
  • Anything that may be odd or unintuitive is provided with a GitHub comment explaining it.
• All CI checks pass before pinging a reviewer, or provide an explanation if they do not.
• The PR title matches the changelog entry's one-line description.

Related Issues

Closes #491