pub fn extract_notebook_content(json_text: &str) -> Option<String>Expand description
Extract the human-readable text from a Jupyter notebook’s cells.
Concatenates each cell’s source (code and markdown) together with textual
outputs (stream text and text/plain results). Non-text outputs such as
image/png data are intentionally skipped to avoid scanning base64 noise.
Returns Some(combined_text) when the notebook parses and yields any text,
otherwise None (the caller falls back to the raw content).