requestAccess() was dispatched onto the background queue used for
AppleScript execution, on the assumption that a blocking call needed to
be off-main. That's backwards for AEDeterminePermissionToAutomateTarget's
consent dialog — like this app's existing NSAlert.runModal() calls, it
needs to run on the main thread/run loop to actually display. Off-main,
it silently returned without ever showing a prompt or changing state.
Also added Log.mail diagnostics on both the status-only check and the
prompting call so a future report of "still doesn't work" has an actual
status code to look at instead of starting from scratch.