0.21.0

Added

• mirrors: keep local folders mirrored into native Google Docs and Sheets. mirrors add <path> --parent <folder> saves a mirror; mirrors sync writes changed files: Markdown becomes a Google Doc with native headings,
  bulleted, numbered and checklist items, tables, code, quotes, links and images; CSV, TSV and XLSX become a
  Google Sheet with typed cells, one tab per worksheet. An update edits in place: a Doc changes only the
  paragraphs that changed, so comments on the rest stay, and a Sheet rewrites only the mirrored range, so other
  tabs, columns and formatting stay. A change made in Google since the last sync stops that file unless
  --replace; a checklist tick may change on either side. - [x] items are written struck through, since Google
  lets no app tick a box. Nothing is ever deleted in Google. mirrors status shows what the next sync would do
  without asking Google; mirrors list and mirrors remove change local settings only. Needs the write grant
  (session start --grant write). DOCX files are not mirrored yet (cli-core 0.379.0 → 0.383.0, cli-base
  0.48.0 → 0.49.0).