feat: migrate to Vue 3.5 + Vite

Faithful 1:1 port of the single-file index.html to a Vite + Vue 3.5
project. All visuals, behavior, translations, quiz logic, scoring,
SVG paint filters, and modifier panel preserved. The previous
single-file build is archived as index.original.html for A/B compare.

Inline onclick handlers in the static template are converted to
Vue's @click bindings — Vue 3 ignores string-valued on* attributes,
which silently broke the qpb-logo "back to landing" navigation.
Inline handlers inside dynamically-injected innerHTML strings
(quiz options, slider, nav buttons) keep working since the browser
parses them; their target functions are exposed on window from
onMounted.

Pinned: vue 3.5.13, vite 6.4.2, @vitejs/plugin-vue 5.2.1.
Zero npm audit vulnerabilities.

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

package.json

@@ -0,0 +1,18 @@
+{
+  "name": "kammergut",
+  "private": true,
+  "version": "0.1.0",
+  "type": "module",
+  "scripts": {
+    "dev": "vite",
+    "build": "vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "vue": "3.5.13"
+  },
+  "devDependencies": {
+    "@vitejs/plugin-vue": "5.2.1",
+    "vite": "6.4.2"
+  }
+}