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/@heroicons/react/24/outline/esm/ReceiptRefundIcon.js

@@ -0,0 +1,26 @@
+import * as React from "react";
+function ReceiptRefundIcon({
+  title,
+  titleId,
+  ...props
+}, svgRef) {
+  return /*#__PURE__*/React.createElement("svg", Object.assign({
+    xmlns: "http://www.w3.org/2000/svg",
+    fill: "none",
+    viewBox: "0 0 24 24",
+    strokeWidth: 1.5,
+    stroke: "currentColor",
+    "aria-hidden": "true",
+    "data-slot": "icon",
+    ref: svgRef,
+    "aria-labelledby": titleId
+  }, props), title ? /*#__PURE__*/React.createElement("title", {
+    id: titleId
+  }, title) : null, /*#__PURE__*/React.createElement("path", {
+    strokeLinecap: "round",
+    strokeLinejoin: "round",
+    d: "M8.25 9.75h4.875a2.625 2.625 0 0 1 0 5.25H12M8.25 9.75 10.5 7.5M8.25 9.75 10.5 12m9-7.243V21.75l-3.75-1.5-3.75 1.5-3.75-1.5-3.75 1.5V4.757c0-1.108.806-2.057 1.907-2.185a48.507 48.507 0 0 1 11.186 0c1.1.128 1.907 1.077 1.907 2.185Z"
+  }));
+}
+const ForwardRef = /*#__PURE__*/ React.forwardRef(ReceiptRefundIcon);
+export default ForwardRef;