Standardize create-flow option steps on one question-and-options layout and Selection sizes.

Method cards, chips, and the right rail now share the two-column shell; last options clear the footer fade, See all stays under the stack, and the left heading no longer jumps when the list expands.

Co-authored-by: Cursor <cursoragent@cursor.com>

tests/unit/CardStack.test.jsx

@@ -126,6 +126,18 @@ describe("CardStack Component", () => {
     ).toBeInTheDocument();
   });
 
+  test("single-stack See all / Show less is centered, not end-aligned", () => {
+    render(
+      <CardStack cards={SAMPLE_CARDS} hasMore={true} layout="singleStack" />,
+    );
+
+    const toggle = screen.getByRole("button", {
+      name: "See all communication approaches",
+    });
+    expect(toggle.className).toMatch(/\bself-center\b/);
+    expect(toggle.className).not.toMatch(/\bself-end\b/);
+  });
+
   test("calls onCardSelect when a card is clicked", () => {
     const onCardSelect = vi.fn();
     render(<CardStack cards={SAMPLE_CARDS} onCardSelect={onCardSelect} />);