docs(tui): spell out question-sheet scroll shortcuts

Show the complete Alt+arrow bindings in the question-sheet table and explain
Ctrl+arrow and Shift+arrow aliases in the sheet-specific prose. Standalone
modifier labels were being advertised as chords by the catalog drift check.
The existing drift check and the global help catalog remain intact.

Validation: npm test: 66 wrapper + 9 SDK + 446 web passed, 0 failed.
npm run check:web passed: 0 errors, 2 existing img warnings.
git diff --check passed. The prior local/macOS full suite had 15,358 passed
and only the catalog documentation check failed; Linux had 15,350 passed
and the same single failure. The complete final-commit sweep follows.

Author: CodeWhale Bot

docs/KEYBINDINGS.md

@@ -263,10 +263,14 @@ reveal content.
 | `Esc` | Cancel the whole question request |
 | `PageUp` / `PageDown` | Scroll the transcript while keeping the sheet open |
 | `Home` / `End` | Go to the start / latest part of the transcript |
-| `Ctrl`, `Alt`, or `Shift` + `↑` / `↓` | Scroll the transcript three lines |
+| `Alt+↑` / `Alt+↓` | Scroll the transcript three lines |
 | Mouse wheel above the sheet | Scroll the transcript; side work surfaces keep their own input |
 | Mouse wheel over the sheet | Browse the question content without changing the answer or highlight |
 
+While the question sheet is open, `Ctrl+↑` / `Ctrl+↓` and `Shift+↑` / `Shift+↓`
+also scroll the transcript three lines. Plain arrows continue to move the option
+highlight.
+
 After wheel browsing, option navigation or typing brings the highlighted option
 or custom-response text back into view. Transcript scroll keys work in both
 option selection and custom-response typing.