Android: stop over-fetching after local edits and on WS echoes

[dkhalife]

Problem

A single local edit on Android triggers up to 3 full GET /tasks + 3 GET /labels round-trips:

1. TaskRepository.updateTask (or similar) calls syncCoordinator.syncOnce(), which flushes the outbox (necessary) then full-refreshes (not necessary — we just wrote the authoritative state).
2. The server broadcasts a WS event → WebSocketSyncBridge → another syncOnceBlocking → another full refresh.
3. TaskListViewModel / LabelViewModel independently listen to the same WS events and ALSO call refreshTasks() / refreshLabels() → yet another full refresh.

The WS echo alone is sufficient to reconcile authoritative server state. The intuition: writes should only flush; refresh happens on the incoming echo.

Changes

• SyncCoordinator.flushPending(): new flush-only path for locally-initiated mutations. Coalesces with any in-flight sync (the running outbox loop will drain the newly inserted row).
• Repositories: every write-path syncCoordinator.syncOnce() → syncCoordinator.flushPending(). The unused updateTasksFromWebSocket / updateLabelsFromWebSocket helpers (no callers) were removed.
• syncOnceBlocking coalesce: if a syncOnce job is already running, join it instead of queueing a duplicate full cycle. This also dedupes the app-start + first-screen double sync.
• WebSocketSyncBridge: TASK_EVENTS → SYNC_EVENTS, now also includes label_* events so per-ViewModel WS listeners can go away.
• LabelViewModel: WS listener dropped entirely; DB Flow observation covers it. WebSocketManager dep removed.
• TaskListViewModel: WS listener trimmed to only refresh completed tasks on relevant events — that endpoint is not covered by SyncCoordinator.refreshAll.

Net effect

A single local edit now costs: 1 write request + 1 debounced background refresh (from the WS echo, ~500 ms later). Down from up to 7 round-trips. Remote changes (other clients) still reconcile in ≤500 ms via the same WS path.

[Copilot]

Pull request overview

Reduces redundant full refreshes on Android by separating “flush outbox” from “refresh from server”, and consolidating WebSocket-triggered reconciliation through WebSocketSyncBridge + SyncCoordinator.

Changes:

• Introduces SyncCoordinator.flushPending() and updates task/label write paths to flush-only (no immediate full refresh).
• Coalesces syncOnceBlocking() calls to avoid duplicate full sync cycles.
• Expands WebSocketSyncBridge to trigger reconciliation for both task and label WS events; trims/removes per-ViewModel WS listeners accordingly.

Show a summary per file

File	Description
android/app/src/main/java/com/dkhalife/tasks/viewmodel/TaskListViewModel.kt	Limits WS-driven refreshes to completed-task endpoint only.
android/app/src/main/java/com/dkhalife/tasks/viewmodel/LabelViewModel.kt	Removes WS listener dependency; relies on repository/DB updates.
android/app/src/main/java/com/dkhalife/tasks/repo/TaskRepository.kt	Switches write paths from syncOnce() to flushPending(); removes unused WS helper.
android/app/src/main/java/com/dkhalife/tasks/repo/LabelRepository.kt	Switches write paths from syncOnce() to flushPending(); removes unused WS helper.
android/app/src/main/java/com/dkhalife/tasks/data/sync/WebSocketSyncBridge.kt	Broadens event set (tasks + labels) that triggers debounced reconciliation sync.
android/app/src/main/java/com/dkhalife/tasks/data/sync/SyncCoordinator.kt	Adds flush-only path and modifies syncOnceBlocking() to join in-flight work.

Copilot's findings

• Files reviewed: 6/6 changed files
• Comments generated: 3