feat: initial web3 corporate style guide

- Extract design tokens (colors, typography, spacing) from dao-marketplace
- Build component CSS: base, card, button, forms
- Create interactive Vite showcase app with tabbed navigation
- Add README, .gitignore, AGENTS.md
- Build passes (vite v8.2.2)

vite.config.ts

@@ -0,0 +1,8 @@
+import { defineConfig } from 'vite';
+import react from '@vitejs/plugin-react';
+
+export default defineConfig({
+  plugins: [react()],
+  root: '.',
+  publicDir: 'public',
+});