feat: port all template categories to JSON format

- Ported Minimalist templates to JSON (Swiss Grid, Brutalist, etc.)
- Ported Tech templates to JSON (SaaS, Terminal, Cyberpunk, etc.)
- Ported Creative templates to JSON (Art Gallery, Zine, Pop Art, etc.)
- Ported Industrial templates to JSON (Blueprint, Factory, Schematic, etc.)
- Ported Nature templates to JSON (Botanical, Ocean, Mountain, etc.)
- Ported Lifestyle templates to JSON (Cookbook, Travel, Coffee House, etc.)
- Ported Vintage templates to JSON (Art Deco, Medieval, Retro 80s, etc.)
- Updated README.md to reflect the new JSON-based style system (example configuration and contribution workflow)
- Completed migration of over 150 styles to the new architecture

postcss.config.js

@@ -0,0 +1,5 @@
+export default {
+  plugins: {
+    '@tailwindcss/postcss': {},
+  },
+}