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/tailwindcss/lib/postcss-plugins/nesting/index.js

@@ -0,0 +1,21 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+Object.defineProperty(exports, "default", {
+    enumerable: true,
+    get: function() {
+        return _default;
+    }
+});
+const _plugin = require("./plugin");
+const _default = Object.assign(function(opts) {
+    return {
+        postcssPlugin: "tailwindcss/nesting",
+        Once (root, { result  }) {
+            return (0, _plugin.nesting)(opts)(root, result);
+        }
+    };
+}, {
+    postcss: true
+});