Unify create-flow gutters, viewport height, and action-bar width so tablet and wide layouts stay aligned with step content.

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

app/(app)/create/loading.tsx

@@ -6,7 +6,7 @@
 export default function CreateFlowRouteLoading() {
   return (
     <div
-      className="flex h-screen min-h-0 flex-col overflow-hidden bg-[var(--color-surface-default-primary)]"
+      className="flex h-dvh max-h-dvh min-h-0 flex-col overflow-hidden bg-[var(--color-surface-default-primary)]"
       aria-busy="true"
       aria-live="polite"
     >