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/readdirp/index.d.ts

@@ -0,0 +1,43 @@
+// TypeScript Version: 3.2
+
+/// <reference types="node" lib="esnext" />
+
+import * as fs from 'fs';
+import { Readable } from 'stream';
+
+declare namespace readdir {
+  interface EntryInfo {
+    path: string;
+    fullPath: string;
+    basename: string;
+    stats?: fs.Stats;
+    dirent?: fs.Dirent;
+  }
+
+  interface ReaddirpOptions {
+    root?: string;
+    fileFilter?: string | string[] | ((entry: EntryInfo) => boolean);
+    directoryFilter?: string | string[] | ((entry: EntryInfo) => boolean);
+    type?: 'files' | 'directories' | 'files_directories' | 'all';
+    lstat?: boolean;
+    depth?: number;
+    alwaysStat?: boolean;
+  }
+
+  interface ReaddirpStream extends Readable, AsyncIterable<EntryInfo> {
+    read(): EntryInfo;
+    [Symbol.asyncIterator](): AsyncIterableIterator<EntryInfo>;
+  }
+
+  function promise(
+    root: string,
+    options?: ReaddirpOptions
+  ): Promise<EntryInfo[]>;
+}
+
+declare function readdir(
+  root: string,
+  options?: readdir.ReaddirpOptions
+): readdir.ReaddirpStream;
+
+export = readdir;