Drive widget and alarm sync with AlarmManager and minute ticks across all app states.

Replace the unreliable self-rescheduling WorkManager chain with two state-aware
drivers: an exact AlarmManager alarm re-armed every 5 minutes (works foreground,
in recents, and when killed) and a dynamic ACTION_TIME_TICK receiver that syncs
every minute while the process is alive. Both run a shared TimeTodoBackgroundSync
that refreshes the widget and registers/cancels today's Time TODO notifications.
Re-arm the alarm on boot and package replace.

Co-authored-by: Cursor <cursoragent@cursor.com>