Reproduction on main a452c2dfdc, web dev server (T3CODE_DEV_SEED=0), Chromium preview 1280x800, 4 threads seeded via `t3 thread start`.
Logger: MutationObserver on [aria-live]/[role=status] text + focusin aria-label, timestamps from install.
5077ms KEY: ctrl+shift+[ previous thread
5290ms focus: Message Fix login bug
5800ms live(status): Syncing messages...
8731ms KEY: ctrl+shift+[ previous thread
9002ms focus: Message Fix login bug
12827ms KEY: ctrl+shift+[ previous thread
13054ms focus: Message Add dark mode
17389ms KEY: ctrl+shift+s settle
17753ms focus: Message Fix login bug
18023ms live(polite): Settled 1 thread, Ctrl+Z to undo
22387ms KEY: ctrl+z undo            -> "Add dark mode" restored in sidebar; NO announcement
28272ms KEY: ctrl+shift+p pin       -> "Fix login bug" pinned (pin icon, moved to top); NO announcement
47439ms KEY: ctrl+shift+m open model picker
47854ms focus: combobox
50035ms KEY: ctrl+shift+arrowdown next provider
51111ms live(polite): Favorites
60343ms live(polite): Codex
(ctrl+1-9 thread jump / model jump are `isDesktop`-only bindings; not reachable in a browser)