[Bug] Legacy model restore warnings are ignored by the upload UI

[lil-aditya]

Summary

Uploading an older model archive can succeed on the backend but appear to do nothing in the browser.

For legacy archives, the backend intentionally returns a warning response from API/Routes/Upload/UploadRoute.py with a payload like status_code: "warning" plus message_warning. However, the upload success handler in WebAPP/Classes/Base.Class.js does not handle that warning path, so the UI does not append the restored model, does not close the restore modal, and does not show the upgrade guidance.

As a result, users can successfully restore a legacy model on disk but think the restore failed because the frontend never reflects the completed action.

Expected behavior

If the backend returns a restore response with:

• status_code: "warning"
• a valid casename
• a legacy-upgrade message_warning

the frontend should still treat the restore as successful and:

• add the restored model to the list
• close the restore modal
• show the success message
• also show the upgrade warning / migration guidance

Only non-restoring warnings such as "model already exists" should remain warning-only and avoid mutating the UI.

Reproduction steps

1. Start the application locally.
2. Open the "Restore" / upload modal for case archives.
3. Upload a legacy model archive that triggers the backend legacy-warning path, such as a model with osy-version 4.0, 4.5, or 4.9.
4. Wait for the upload request to complete successfully.
5. Observe that the backend returns a warning restore response, but the frontend does not add the model to the UI and does not close the modal.

Optional verification:

1. Inspect the network response for the upload request.
2. Confirm the response contains status_code: "warning", casename, and message_warning.
3. Compare that with the browser behavior, which remains unchanged.

Environment

• OS: Windows
• Browser: Chromium-based browser (Chrome / Edge)
• App state: reproduced on main before applying a frontend fix
• Relevant frontend file: WebAPP/Classes/Base.Class.js
• Relevant backend file: API/Routes/Upload/UploadRoute.py

Logs or screenshots

Example backend response payload:

{
  "response": [
    {
      "message_warning": "You have restored a model created in a earlier version...",
      "message": "Model LegacyModel have been uploaded!",
      "status_code": "warning",
      "casename": "LegacyModel"
    }
  ]
}

Observed frontend behavior after this response:

no restored model is appended to the case list
restore modal stays open
upgrade warning is not surfaced to the user

Related work checked

I checked the current restore / archive-related work and did not find an issue specifically covering the frontend warning-handling gap for legacy restores.

Related areas reviewed:

• backend restore response handling in API/Routes/Upload/UploadRoute.py
• frontend upload success handling in WebAPP/Classes/Base.Class.js
• recent archive / zip / restore-related work does not appear to address this specific UI behavior gap

Proposed track

None