docs: correct embedding similarity example conclusion

[hahahahahayesyeseys]

Fixes #1601.

The final embedding example currently says sentences 1 and 2 are more similar, contradicting both the saved outputs and the preceding semantic comparison. Sentences 1 and 3 have the smaller Euclidean distance (0.593 vs. 0.715) and higher cosine similarity (0.824 vs. 0.745).

Correct the concluding Markdown cell and include these values to explain the ranking. Notebook code and saved outputs are unchanged.

Validation:

• Parsed the notebook JSON and checked both saved metric rankings against the conclusion: the original conclusion failed; the updated conclusion passed.
• Verified that all other notebook cells and metadata are unchanged.
• git diff --check passed.

The embedding model and full notebook were not rerun; this documentation correction uses the existing saved outputs. AI assistance was used to inspect the example, make this edit, and prepare this PR.