Replace individual new-note emails with an administrator digest

For the established (legacy) Volunteer Management portal. These steps differ from the newer Volunteer Management interface. Administrator controls require the appropriate school or volunteer-management permissions.

In established VMS Administrators, locate the staff member and set Digest Email Notifications to Yes, then confirm. New volunteer-note notifications to eligible handlers are queued into the daily digest instead of being sent individually when this setting is enabled. Setting it to No restores individual notifications; it is not an off switch. This also affects other supported digest notifications and does not confirm a note-only mute. Updated-note notifications have a separate send path, so inspect the actual message type if those still arrive individually. The setting is not shown on every system-school administrative view.