`crdt_sync` is pure Dart so it can run from CLI tools and headless systemd
jobs, which means it takes closures instead of depending on
flutter_secure_storage and google_sign_in. Every Flutter app then wrote the
same ~390 lines to supply them, and five apps ended up carrying near-identical
copies of firebase_backend.dart.
Those copies drifted. `todo` gained an opt-out flag and a seeded-session path
that home_inventory and wake_alarm never received, so the same bug was fixed
in one copy and left live in the others -- which is the actual cost being paid
here, not the line count.
This package owns that glue once: the keystore adapter, the persisted
per-install device id, the account store and a one-call bootstrap. A new app
needs a SyncApp const and `openSync(kApp)`.
The wrapper routes are a parameter rather than a constant, because todo's copy
hardcoded its own `~/.config/todo/firebase_auth.json`. An extraction only one
app could adopt would be worse than the copies.
Also documents what made this hard to find: crdt_sync_dart's README covered
only the *old* GitHub transport and never mentioned the Firebase surface at
all, and sync_settings_ui -- a complete drop-in settings screen -- had no
README whatsoever.
The five existing apps stay on their copies and on crdt_sync_dart-v0.10.0.
Migration is forward-only and those fallbacks are load-bearing; converging
them is a separate task, and the README says so.
35 tests, 100% line coverage, no suppressions.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01CFSGeWxHPY5rHUGrPqhcmG
