org-gdocs — publish a projection of an org-mode document to Google Docs and
sync reviewer comments back into the org file.
Org-mode is the single source of truth; Google Docs is a collaboration surface for comments only. This crate owns all testable logic (org projection, the Google API client, comment anchoring, file writeback); the companion Emacs package is a thin shell over the binary.
See docs/plans/org-gdocs.md for the architecture and invariants this crate
is built against.