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/picocolors/README.md

@@ -0,0 +1,21 @@
+# picocolors
+
+The tiniest and the fastest library for terminal output formatting with ANSI colors.
+
+```javascript
+import pc from "picocolors"
+
+console.log(
+  pc.green(`How are ${pc.italic(`you`)} doing?`)
+)
+```
+
+- **No dependencies.**
+- **14 times** smaller and **2 times** faster than chalk.
+- Used by popular tools like PostCSS, SVGO, Stylelint, and Browserslist.
+- Node.js v6+ & browsers support. Support for both CJS and ESM projects.
+- TypeScript type declarations included.
+- [`NO_COLOR`](https://no-color.org/) friendly.
+
+## Docs
+Read **[full docs](https://github.com/alexeyraspopov/picocolors#readme)** on GitHub.