Create flow UX updates

app/create/hooks/useCreateFlowMdUp.ts

@@ -0,0 +1,29 @@
+"use client";
+
+import { useEffect, useState } from "react";
+import { useMediaQuery } from "../../hooks/useMediaQuery";
+
+/**
+ * Matches design-system `md` (`--breakpoint-md`, 640px in `app/tailwind.css`).
+ * Use with Tailwind `md:` / `max-md:` utilities in create-flow pages.
+ */
+const CREATE_FLOW_MIN_WIDTH_MD = "(min-width: 640px)";
+
+/**
+ * True at or above the create-flow `md` breakpoint (desktop-oriented layout).
+ *
+ * `useMediaQuery` initializes to `false` on the server and first client render
+ * to avoid hydration mismatches. We combine it with a post-mount flag so the
+ * first paint matches the intended desktop layout until `matchMedia` runs.
+ */
+export function useCreateFlowMdUp(): boolean {
+  const [isMounted, setIsMounted] = useState(false);
+  const isMdOrLarger = useMediaQuery(CREATE_FLOW_MIN_WIDTH_MD);
+
+  useEffect(() => {
+    // eslint-disable-next-line react-hooks/set-state-in-effect -- intentional: defer until mount for SSR/first-paint alignment
+    setIsMounted(true);
+  }, []);
+
+  return !isMounted || isMdOrLarger;
+}