v12.17.1

Offline correctness fixes.

• An offline add keeps one id. The id the app is given is now the id the record is created under when it syncs. Before, the server created the record under a different id, so an offline edit to a record added offline was sent to an id that did not exist and refused. (The same fix the JS SDK made earlier.)
• A refused offline add no longer lingers. When the server refuses an add made offline, the record is removed from the device's saved record and saved lists; the conflict keeps the user's data.
• Writes held behind a conflict stay held. Later queued changes to a record with an undecided conflict now wait across sync passes and restarts, instead of each becoming its own conflict on the next pass.
• Tested: the queued add's id, an add-then-edit chain replayed onto one id, the refused add leaving the saved copies, and a held write on a later pass.