Adds a new HUD label in the upper-left of the 3D view that reads
"Filter : <name(s)>" whenever a cell, property, or per-view data
filter is active. The label is hidden when nothing is enabled.
Names are joined per the source collection's AND/OR combine mode, and
contributions from different collections are concatenated with ", ".
On Eclipse views the unified RimFilterInViewCollection is used as the
single anchor; GeoMech views aggregate cell and GeoMech property
filters directly.