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/is-binary-path/index.d.ts

@@ -0,0 +1,17 @@
+/**
+Check if a file path is a binary file.
+
+@example
+```
+import isBinaryPath = require('is-binary-path');
+
+isBinaryPath('source/unicorn.png');
+//=> true
+
+isBinaryPath('source/unicorn.txt');
+//=> false
+```
+*/
+declare function isBinaryPath(filePath: string): boolean;
+
+export = isBinaryPath;