Add single-file logo generator with accessibility fixes

Single-file HTML/CSS/JS logo generator. Accessibility and
native-HTML improvements over the original draft:

- viewport meta for mobile zoom/reflow
- programmatic label association (label[for], aria-label,
  aria-labelledby) for all form controls
- visible keyboard focus indicators (restored outline)
- proper heading hierarchy (h1/h2)
- native <details>/<summary> for panel show/hide (replaces JS toggle)
- native <form> reset via <button type="reset"> (replaces manual
  field-by-field reset and the duplicated DEFAULTS object)
- AA-safe text contrast for hints/hex labels

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

package.json

@@ -0,0 +1,16 @@
+{
+  "name": "demo-ecmascript",
+  "version": "1.0.0",
+  "description": "",
+  "repository": {
+    "type": "git",
+    "url": "ssh://tengo@git.librete.ch:41240/public/demo-ecmascript.git"
+  },
+  "license": "WTFPL",
+  "author": "",
+  "type": "module",
+  "main": "index.html",
+  "scripts": {
+    "test": "echo \"Error: no test specified\" && exit 1"
+  }
+}