Add Astro port of the logo generator

Astro page (src/pages/index.astro) renders the markup statically from
the shared src/logo.js defaults; interactivity lives in a bundled
client <script> that imports the same core (inlineTextShadow,
cssOutput) and wires the DOM — no framework runtime. Keeps the
accessibility markup (labels, aria, <details>/<summary>, focus rings)
and native <form> reset.

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

package.json

@@ -0,0 +1,20 @@
+{
+  "name": "demo-ecmascript-astro",
+  "version": "1.0.0",
+  "description": "LIBRETECH logo generator — Astro (Vite)",
+  "repository": {
+    "type": "git",
+    "url": "ssh://tengo@git.librete.ch:41240/public/demo-ecmascript.git"
+  },
+  "license": "WTFPL",
+  "type": "module",
+  "scripts": {
+    "dev": "astro dev",
+    "build": "astro build",
+    "preview": "astro preview",
+    "astro": "astro"
+  },
+  "dependencies": {
+    "astro": "^5.1.1"
+  }
+}