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/autoprefixer/lib/hacks/appearance.js

@@ -0,0 +1,23 @@
+let Declaration = require('../declaration')
+let utils = require('../utils')
+
+class Appearance extends Declaration {
+  constructor(name, prefixes, all) {
+    super(name, prefixes, all)
+
+    if (this.prefixes) {
+      this.prefixes = utils.uniq(
+        this.prefixes.map(i => {
+          if (i === '-ms-') {
+            return '-webkit-'
+          }
+          return i
+        })
+      )
+    }
+  }
+}
+
+Appearance.names = ['appearance']
+
+module.exports = Appearance