Keybinding hint bar now groups paired actions into a single combined hint

The dimmed hint text that Claude Code shows under menus and dialogs, listing available keyboard shortcuts, now groups certain paired actions into a single combined hint instead of listing them separately. The pairs affected are select previous/next, confirm previous/next, and tabs next/previous; each now shows both key combinations together in one entry. Separately, the underlying logic that figures out which part of the screen a keypress applies to can now fall back to a nested chain of scopes when nothing nearby defines one directly.