Live chat rendered the recommended unit-mix as a garbled rank-hyphen-type
list ("2-1-к", "3-2-к" = "rank 2: 1-к"). Add rule 6 to chat_system@v2:
list квартирография/segments by clean TYPE (студия / 1-к / 2-к / 3-к /
80+ м²) + share %, no ordinal-number-hyphen-type concatenation. Bumped
prompt version 1->2 (versioned-prompt convention). Test locks v2 + the rule.
Refs #957