swap home banners, 3s autoplay, animated rec scroll thumb

public/assets/ark-library/banners/README.md

@@ -0,0 +1,9 @@
+# Home banner slider images
+
+Drop banner images here as `banner-1.png`, `banner-2.png`, `banner-3.png`, `banner-4.png`.
+
+- Used by `src/components/FigmaBanner.tsx` (home page slider on `/`)
+- Recommended size: 780 × 400 px (2x of mobile 390 × 200)
+- Format: PNG or WebP; PNG keeps the existing pipeline
+- Filenames are fixed; replace the file to swap a slide
+- To add more slides, append to `BANNER_SLIDES` in `FigmaBanner.tsx`