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/vendor.js

@@ -0,0 +1,14 @@
+module.exports = {
+  prefix(prop) {
+    let match = prop.match(/^(-\w+-)/)
+    if (match) {
+      return match[0]
+    }
+
+    return ''
+  },
+
+  unprefixed(prop) {
+    return prop.replace(/^-\w+-/, '')
+  }
+}