DOC Sync six drifting Jupytext notebook pairs

[Roman Lutz (romanlutz)]

Description

Six documentation notebooks had drifted from their paired Jupytext percent files. This made code cells inconsistent between rendered notebooks and reviewable Python sources, including missing markdown cell separators and imports in the WebSocket Copilot target example.

Synchronize each pair from its authoritative content while preserving existing notebook outputs and metadata. The WebSocket and Playwright pairs merge the valid imports and cell boundaries from both representations; the remaining pairs align wording or remove stray code-cell whitespace. Jupytext-equivalent metadata differences outside these six pairs are intentionally left unchanged to avoid generated churn.

Tests and Documentation

• Ran a repository-wide uv run jupytext --diff audit to identify the six drifting pairs.
• Confirmed uv run jupytext --diff <file.py> <file.ipynb> produces no diff for every affected pair.
• Ran targeted uv run ruff check and uv run ruff format --check on the changed percent files.
• Ran git diff --check.
• Commit hooks passed documentation structure, notebook sanitation, Ruff, and Jupyter Ruff checks.