_reconcileElapsedTime() runs off a Dart Stopwatch, which is CLOCK_MONOTONIC
and does not advance while the device is suspended - exactly the state an
RTC_WAKEUP expiry alarm fires in. The "did this drop happen at the deadline"
test therefore came out false after any sleep, and the screen-off expiry (the
common one) still showed no reason in the UI.
Each successful sync now records an absolute DateTime deadline, and the
tunnel-dropped branch compares against that instead.
Co-Authored-By: Claude Opus 5 <[email protected]>