Minor styling

Now, when you click "Run Fractal," the Fractal tool will execute in Galaxy, and the resulting image will be displayed in the UI.  You can also change the `fractal_type` using the input field. This demonstrates the complete MVVM flow, with data binding, Pydantic validation, and the interaction between the View, ViewModel, and Model.

This revised structure breaks down the implementation into smaller, more manageable steps, with demonstrations after each stage to show the progress and confirm that each part is working as expected. This addresses the feedback about making too many code changes at once and improves the learning experience.

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If you don't want Trame to launch a tab by default, you can instead run ```poetry run app --server```.