v3 retired the equipment-Tag binding; IUnsTreeService.LoadTagsForEquipmentAsync
always returned empty, had no production caller, and EquipmentTagRow plus the
always-zero tagCounts / EquipmentRow.TagCount plumbing existed only to feed it.
All removed; the equipment badge count (virtual tags) is unchanged.
Refs #745
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty