Tasks

• T001 Specify and plan in specs/025-board-history-subset/.
• T002 [US1] Reproduce missing notice with native fixture in crates/signaltty-gui/src/app_tests.rs.
• T003 [US1] Add notice in crates/signaltty-gui/src/board.rs and inspect native captures.
• T004 Review, update docs/06-gui-toolkit.md and verify-signaltty board coverage; run scripts/verify.sh full.
• T005 Publish/link PR and merge after checks/review pass. Dependencies: sequential; read-only reviewer independent.

PR #43 merged at e6d1845; current-main full gate passed in full-6ueb2fdc (26 isolated GTK tests), CI run 37826589815 passed.