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/reusify/tsconfig.json

@@ -0,0 +1,11 @@
+{
+  "compilerOptions": {
+    "target": "es6",
+    "module": "commonjs",
+    "noEmit": true,
+    "strict": true
+  },
+  "files": [
+    "./reusify.d.ts"
+  ]
+}