Development record

.abcd/development/brief/04-surfaces/27-implement.md:117 and following list the conditions a second session's refusal line names. A second session setting the window's mode is refused with condition `second_session_sets_no_mode` (internal/core/implement/session.go:341), which no chapter or command page names. .abcd/development/brief/04-surfaces/27-implement.md:88 states the rule without the condition.