docs(design): remove SVG, use PNG logo only

SVG icon is no longer in use. public/logo.png (1024x1024 RGBA) is
the single logo asset. DESIGN.md updated accordingly: SVG snippet
removed, wordmark pattern and <head> references updated to PNG.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

node_modules/tailwindcss/scripts/create-plugin-list.js

@@ -0,0 +1,10 @@
+import { corePlugins } from '../src/corePlugins'
+import fs from 'fs'
+import path from 'path'
+
+let corePluginList = Object.keys(corePlugins)
+
+fs.writeFileSync(
+  path.join(process.cwd(), 'src', 'corePluginList.js'),
+  `export default ${JSON.stringify(corePluginList)}`
+)