feat: compose page + Framer Motion animations + reduced-motion support

vitest.setup.ts

@@ -17,3 +17,20 @@ if (typeof window !== 'undefined' && !('IntersectionObserver' in window)) {
   window.IntersectionObserver = IntersectionObserverStub;
   global.IntersectionObserver = IntersectionObserverStub;
 }
+
+// jsdom lacks matchMedia; usePrefersReducedMotion() calls it in useEffect.
+// Note: vitest's jsdom environment pre-defines `matchMedia` as an own property
+// set to `undefined`, so `'matchMedia' in window` is true even though it isn't
+// a function — guard on typeof instead of `in`.
+if (typeof window !== 'undefined' && typeof window.matchMedia !== 'function') {
+  window.matchMedia = (query: string) => ({
+    matches: false,
+    media: query,
+    onchange: null,
+    addEventListener: () => {},
+    removeEventListener: () => {},
+    addListener: () => {},
+    removeListener: () => {},
+    dispatchEvent: () => false,
+  }) as unknown as MediaQueryList;
+}