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/20/solid/SpeakerXMarkIcon.js

@@ -0,0 +1,22 @@
+const React = require("react");
+function SpeakerXMarkIcon({
+  title,
+  titleId,
+  ...props
+}, svgRef) {
+  return /*#__PURE__*/React.createElement("svg", Object.assign({
+    xmlns: "http://www.w3.org/2000/svg",
+    viewBox: "0 0 20 20",
+    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: "M10.047 3.062a.75.75 0 0 1 .453.688v12.5a.75.75 0 0 1-1.264.546L5.203 13H2.667a.75.75 0 0 1-.7-.48A6.985 6.985 0 0 1 1.5 10c0-.887.165-1.737.468-2.52a.75.75 0 0 1 .7-.48h2.535l4.033-3.796a.75.75 0 0 1 .811-.142ZM13.78 7.22a.75.75 0 1 0-1.06 1.06L14.44 10l-1.72 1.72a.75.75 0 0 0 1.06 1.06l1.72-1.72 1.72 1.72a.75.75 0 1 0 1.06-1.06L16.56 10l1.72-1.72a.75.75 0 0 0-1.06-1.06L15.5 8.94l-1.72-1.72Z"
+  }));
+}
+const ForwardRef = /*#__PURE__*/ React.forwardRef(SpeakerXMarkIcon);
+module.exports = ForwardRef;