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/16/solid/esm/UserGroupIcon.js

@@ -0,0 +1,22 @@
+import * as React from "react";
+function UserGroupIcon({
+  title,
+  titleId,
+  ...props
+}, svgRef) {
+  return /*#__PURE__*/React.createElement("svg", Object.assign({
+    xmlns: "http://www.w3.org/2000/svg",
+    viewBox: "0 0 16 16",
+    fill: "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", {
+    d: "M8 8a2.5 2.5 0 1 0 0-5 2.5 2.5 0 0 0 0 5ZM3.156 11.763c.16-.629.44-1.21.813-1.72a2.5 2.5 0 0 0-2.725 1.377c-.136.287.102.58.418.58h1.449c.01-.077.025-.156.045-.237ZM12.847 11.763c.02.08.036.16.046.237h1.446c.316 0 .554-.293.417-.579a2.5 2.5 0 0 0-2.722-1.378c.374.51.653 1.09.813 1.72ZM14 7.5a1.5 1.5 0 1 1-3 0 1.5 1.5 0 0 1 3 0ZM3.5 9a1.5 1.5 0 1 0 0-3 1.5 1.5 0 0 0 0 3ZM5 13c-.552 0-1.013-.455-.876-.99a4.002 4.002 0 0 1 7.753 0c.136.535-.324.99-.877.99H5Z"
+  }));
+}
+const ForwardRef = /*#__PURE__*/ React.forwardRef(UserGroupIcon);
+export default ForwardRef;