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/postcss-js/index.mjs

@@ -0,0 +1,8 @@
+import index from './index.js'
+
+export default index
+
+export const objectify = index.objectify
+export const parse = index.parse
+export const async = index.async
+export const sync = index.sync