Worker: pings every tracked device on a presence sweep (hourly in business
hours plus midnight) and records last online; inventory reports whether a
device was found in AD and SCCM; monitors from WmiMonitorID; snapshots of
the last reachable state replace "Cached"; newly tracked devices are swept
and published first; totals count source devices only; per-type timing in
Worker-State.
Front end: details dialog shows presence, reasons instead of N/A,
"Waiting for worker...", monitors and snapshot times, and refreshes in
place; Custom View gains Days Offline, Last Online, Found In and monitor
columns; manual pair changes show immediately; sync dialog shows timing by
type. Custom View gets a large scrollbar; "Exactly ticked" filter.