fix(widget): dedup rapid completeTask taps on the same task

CompleteWorker.enqueue used a plain WorkManager.enqueue(), which allows
unlimited concurrent OneTimeWorkRequests. A rapid double-tap on the same
row (plausible since the checkbox doesn't visually update until the full
async round-trip -- complete() -> fetchAndPersist() -> updateAll() --
finishes) could spawn two independent, unordered CompleteWorker runs for
the same task, each doing its own fetchAndPersist(); a second worker's
fetch started before the first worker's complete() call had actually
landed server-side could persist a stale snapshot after the first
worker's correct one.

Now uses enqueueUniqueWork("complete_$id", KEEP, ...) so a tap on a task
that already has a completion in flight is dropped rather than racing a
second worker. Different task ids remain independent.

0 files changed, 0 insertions, 0 deletions