0.5.0

Added

• CLI update notice: human commands print a one-line stderr notice when a
  newer release is on npm (24h cache, silent offline, NO_UPDATE_NOTIFIER
  respected, serve stdout untouched).
• README install prompt block at the top for one-paste AI setup.

Changed

• Raise extraction fidelity: unit text renders tables as Markdown and the
  manifest carries a titles[] outline, so outline-first reads need no text
  fetch. docx gains header/footer units, tracked-change tagging and comments;
  xlsx renders number formats, skips hidden rows/sheets with warnings, and
  fills merged cells; pptx follows SmartArt/chart references with warning
  fallback, dedupes master text, and skips note placeholders.
• Releases now also cut a GitHub Release from the CHANGELOG section.