Add Jupyter notebook for Fashion-MNIST confusion matrix visualization

[Ansh911]

This pull request adds a Jupyter notebook that demonstrates evaluation of a model on the Fashion-MNIST dataset using a confusion matrix.

The notebook includes:

• Loading and preprocessing Fashion-MNIST data
• Model prediction evaluation
• Confusion matrix visualization using seaborn and matplotlib

The notebook is self-contained and can be run after installing the required Python dependencies.

[zalando-compr-opensource]

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