Fix streaming interruption

[brichet]

There is an issue when interrupting the LLM (stop button), it seems that the answer if fully populated in the debug output, but not in the frontend. It is probably an issue with the interruption handling, let's fix it in a follow up PR.

Message in the chat

Debug output

$ cat /tmp/jupyter-ai-tutor/2026-07-09_12-48-05_jupyter_tutor_answer.txt 
The error message indicates that `np` is not defined, which means the NumPy library hasn't been imported. However, the exercise description mentions there's a typo in the NumPy function call, not an import issue.

Let's focus on the line that the exercise description points to:

```python
x = np.linsapce(0, 2 * np.pi, 100)  # <-- look carefully at this line
```

The function name `linsapce` looks incorrect. Think about what the correct NumPy function is for creating linearly spaced values. It's a very common function used for this purpose.

Once you fix that typo, you'll also need to make sure NumPy is properly imported at the top of your notebook (usually with `import numpy as np`). The same applies to matplotlib's pyplot, which is typically imported as `import matplotlib.pyplot as plt`.

The rest of the code looks correct for plotting sine and cosine waves. The plotting commands are properly structured with labels, colors, and other formatting elements.

Originally posted by @brichet in #14 (review)