fa-comments mark in the single icon slot — the plural bubble form, because both single-bubble marks (fa-comment-alt-dots, fa-comment-dots) already read as SMS. The sub-channel is NOT shown at list density (08-06 ruling). The row has exactly one icon slot, one generalised actor word and one direction arrow, and it shows the class of sender because that is what triage needs; Website vs Facebook vs Instagram is revealed in the conversation header and on the bubble, never in the row.