ruff: ignore I001/F401 in notebooks (teaching artifacts)

Notebook cells keep illustrative imports (e.g. WebhookSink shown next to a
swap comment) and per-cell import order; consistent with examples/ and tests/.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: raullenchai

pyproject.toml

@@ -77,3 +77,6 @@ ignore = ["E501"]
 "retina/track.py" = ["B007"]
 "examples/*" = ["I001"]
 "tests/*" = ["I001"]
+# Notebooks are teaching artifacts: allow illustrative imports (e.g. showing
+# `WebhookSink` next to a swap comment) and unsorted cell imports.
+"notebooks/*" = ["I001", "F401"]