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/supports-preserve-symlinks-flag/index.js

@@ -0,0 +1,9 @@
+'use strict';
+
+module.exports = (
+// node 12+
+	process.allowedNodeEnvironmentFlags && process.allowedNodeEnvironmentFlags.has('--preserve-symlinks')
+) || (
+// node v6.2 - v11
+	String(module.constructor._findPath).indexOf('preserveSymlinks') >= 0 // eslint-disable-line no-underscore-dangle
+);