Bug Report

Description:
When attempting to copy the "Write Coder on Coder" template, users get stuck in the UI without any error indication, even though the backend /templates endpoint returns a validation error.

Steps to Reproduce:

1. Attempt to copy the "Write Coder on Coder" template
2. Process gets stuck in the UI with no error message shown

Expected Behavior:
The UI should display the validation error to inform the user why the operation failed.

Actual Behavior:

• UI appears stuck/frozen with no error indication
• Backend correctly returns validation error: Template with name "coder-devcontainer" already exists
• Error response includes proper validation details but UI doesn't surface them

UI View

Backend Error Response:

{
    "message": "Template with name \"coder-devcontainer\" already exists.",
    "validations": [
        {
            "field": "name",
            "detail": "This value is already in use and should be unique."
        }
    ]
}

Impact:

• Users are unable to understand why template copying fails
• Multiple users have encountered this issue
• Similar validation error handling issues exist in other parts of the UI

Additional Context:

• This appears to be part of a broader pattern where validation errors from the backend are not properly surfaced in the frontend
• Multiple attempts by the same user result in the same silent failure
• Issue has been ongoing for some time

Reporter: @U03C7NBLPBM
Additional Context From: @U04T3LN8ASU, @U01GSS807RT