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/@nodelib/fs.walk/out/providers/index.d.ts

@@ -0,0 +1,4 @@
+import AsyncProvider from './async';
+import StreamProvider from './stream';
+import SyncProvider from './sync';
+export { AsyncProvider, StreamProvider, SyncProvider };