add(library): STDF (#527)

Co-authored-by: Enzo Innocenzi <enzo@innocenzi.dev>

README.md

@@ -277,6 +277,7 @@
 - 📚 [Built At Lightspeed](https://www.builtatlightspeed.com/) - Massive directory of 500+ Tailwind templates, starters and UI kits.
 - 📚 [Statichunt](https://statichunt.com/tailwind-templates) - Open source directory of hand-picked free and premium Tailwind templates & Starters.
 - 📚 [Tailkits](https://tailkits.com/) - Curated Tailwind CSS components, templates, UI kits, resources, tools & more.
+- 📚 [STDF](https://stdf.design) - Mobile web component library based on Svelte and Tailwind CSS.
 - 🧩 [TailBlocks](https://mertjf.github.io/tailblocks) - 60+ different ready to use Tailwind CSS blocks.
 - 🧩 [Tailwind Components](https://tailwindcomponents.com) - Community-driven Tailwind CSS component repository.
 - 🧩 [Tailwind Toolbox](https://www.tailwindtoolbox.com) - Templates, components and resources.