On app open, sync made ~4 HTTP round-trips per project even when nothing
had changed. Add a batched pre-sync probe: the client sends a project-wide
content hash for each eligible project in one request, and the server
returns which ones still match so the client can skip syncing them.
- base: ProjectContentHasher (entity hashes + project-data hash, computed
identically on client and server) and probe request/response DTOs
- server: POST /projects/{userId}/sync_probe, recomputing each project's
hash from stored state; skips projects with an in-flight sync session;
400 on a malformed body
- client: cache the hash in the project journal (written at FinalizeSync,
invalidated on any content mutation via one chokepoint); probe is
best-effort and degrades to a full sync on any failure
- backstop: never skip a project with pending entity or project-data work,
so a stale cache can't drop a change
Writing activity is excluded by design (per-device, conflict-free).
Tests: ProjectContentHasher, client/server probe units, and an e2e suite
covering client/server hash agreement, the session gate, auth, and 400s.
Server reclaims a project sync session only for the originating install
(derived from the auth token), so a leaked or cancelled session no longer
blocks the owner; a different active install is still rejected. Client
ends sessions under NonCancellable so end_sync isn't dropped when a sync
coroutine is cancelled.
The protocol doc only referenced writing-activity sync in the flowchart
and an offhand parenthetical. Add a dedicated section explaining the
per-device slot model, the GET/POST endpoints, the own-slot merge
strategy, and why errors are swallowed.
New project-data sync phase runs before entity transfer. The blob is a
single per-project row on the server, hash-checked for conflicts; the
client surfaces a per-field pick-a-side resolver UI when both sides
edited concurrently. Author name is a text field, custom theme uses a
clickable color swatch backed by skydoves/colorpicker-compose, and the
word-count goal is cadence + count. Each opt-in section nulls out its
data when unchecked so the wire signal is unambiguous.
