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>

app/components/cards/CardStack/CardStack.container.tsx

@@ -9,10 +9,11 @@ const DEFAULT_TOGGLE_LABEL = "See all communication approaches";
 
 /**
  * Figma: "Utility / CardStack"; canonical code under `cards/`.
- * Selectable stack of cards with
+ * Selectable stack of {@link Selection} options (`size` `m` tiles or `l` rows) with
  * an optional "see all"/"show less" expand toggle.
- * Expanded default layout matches Flow — Expanded Card Stack (`20768:14820`):
- * 281×142 CardSelection tiles in two columns.
+ * Create-flow method steps use `layout="singleStack"` (size `l`) in the shared
+ * question-and-options shell. Expanded default layout still matches Flow —
+ * Expanded Card Stack (`20768:14820`): 281×142 size-`m` tiles in two columns.
  */
 const CardStackContainer = memo<CardStackProps>(
   ({